Muggles' Guide to Harry Potter/Major Events/Shrieking Shack

Overview
Note that this article concerns only events in the Shrieking Shack that occurred in the book Harry Potter and the Prisoner of Azkaban. The Shrieking Shack does make a brief reappearance in Harry Potter and the Deathly Hallows, but this article does not include those events.

Ron is dragged into a tunnel under the Whomping Willow by a large black dog. Following him, Harry and Hermione are trapped in the Shrieking Shack by Sirius Black, who turns out to be an unregistered Animagus; his Animagus form is the black dog. Though disarmed, Harry manages to get his wand back, and is preparing to kill Sirius who he believes betrayed his parents to Voldemort, but Crookshanks, Hermione's cat, gets in the way. The impasse is broken by the arrival of Remus Lupin, who greets Sirius as a brother. Their explanation of what is going on is interrupted again by Severus Snape, who binds both Sirius and Lupin and prepares to take them away to meet the Dementors. Harry, Hermione, and Ron Disarm Snape, which throws him against a wall and knocks him out. Freed, Lupin and Sirius reveal that Ron's rat, Scabbers, is actually an Animagus, Peter Pettigrew. As they return to the school to turn Pettigrew in, the full moon causes Lupin to assume his Werewolf shape, and Sirius transforms into his dog shape to keep Lupin away from the students. Pettigrew changes to his rat shape and escapes. Sirius is caught by the Dementors, and Harry and Hermione try to rescue him, but are unable to and nearly succumb themselves.

Event Details
This event covers some five chapters in the original book, and therefore even the details must be a bit sketchy. For the full event details, the only recourse would be chapters 17 through 21 of Harry Potter and the Prisoner of Azkaban.

As Harry, Ron, and Hermione head back to the school after visiting Hagrid, the recovered Scabbers seems unusually determined to escape. Scabbers bites Ron, then escapes, with Crookshanks in hot pursuit. Ron catches Scabbers, but a black dog appears, knocking Harry aside and grabbing Ron. The dog drags Ron into a hole under the roots of the Whomping Willow, breaking Ron's leg. Harry, trying to follow, is struck by one of the Willow's flailing branches.

Crookshanks dives under the branches and presses a knot in the tree trunk. The branches fall still; following Ron and the black dog, Harry and Hermione enter a tunnel that leads to the Shrieking Shack. Upstairs, Ron, lying beside a decrepit four-poster bed, warns them it is a trap; the dog is Sirius Black, an Animagus. Black disarms Harry and Hermione with Ron's wand.

Sirius remarks he is glad Harry acted like his father, coming to save his friend rather than running for help; that makes things easier. Ron says Black will have to kill them all, not just Harry, but Black responds there will only be one murder tonight. Harry demands to know if killing twelve Muggles plus Peter Pettigrew were not enough and lunges at the visibly weakened Black, grabbing his wand wrist. Black chokes Harry with his free hand. Hermione kicks Black while Ron grabs his wand hand. Harry breaks away; as he grabs Black's wand, Crookshanks claws his hand. Defenseless, Black asks if Harry is going to kill him. Harry says he knows Black betrayed his parents to Voldemort. Black admits he was responsible but there is more to the story. As Harry decides whether or not to listen, Crookshanks deliberately sits on Black's chest, resisting Black's efforts to remove him.

Professor Lupin suddenly bursts in and disarms Harry, Ron, and Hermione, and asks, "Where is he?" Black points at Ron. Lupin demands, "Why hasn't he shown himself? Unless... you switched... and didn't tell me?" Black nods. Lupin pulls Black to his feet, embracing him. Hermione, sounding betrayed, tells Lupin that she trusted him and protected the secret that he is is a Werewolf. Lupin admits that he is, but he has not been helping Black, nor does he want Harry dead. The Hogwarts staff knows he is a Werewolf; Professor Dumbledore convinced them he was trustworthy. Professor Snape set the Werewolf assignment with the expectation that a student would detect Lupin and give away his secret.

Lupin returns the Trio's wands, placing his own wand in his belt, and asks the Trio to listen. Lupin saw Black's name on the Marauder's Map, a map Lupin helped create when he was a student. Lupin is "Moony." He saw someone on the map with the Trio. Lupin and Black claim Scabbers is actually a Wizard Animagus named Peter Pettigrew.

Harry, Ron, and Hermione insist Lupin and Black must be crazy, Scabbers could not be Peter Pettigrew; Black murdered him twelve years ago. Black says he did try to kill him, but, unknown to him, Peter escaped. Lupin insists that Harry must understand everything before Pettigrew dies. Black acquiesces, but demands Lupin be quick, he wants to commit the murder for which he was imprisoned. When Ron reminds Black there were witnesses who saw him kill Pettigrew and the Muggles, Black contends they were fooled. Hermione points out that Pettigrew is not listed among the seven registered Animagi. Lupin claims there were three unregistered Animagi running around Hogwarts.

Ron, noting a door apparently opening by itself, thinks the Shrieking Shack is haunted, but Lupin claims it is not. The howls the villagers heard were his, not Ghosts. Before there was a potion to allow a Werewolf to retain his mind, the Shrieking Shack was built specifically to confine Lupin during his transformations. The Whomping Willow was planted to guard the tunnel leading to the shack. Terrible as the transformations were, Lupin did have three great friends: Sirius Black, Peter Pettigrew, and James Potter. After discovering he was a Werewolf, rather than shunning their friend, they secretly became Animagi to support him. It took them three years to learn how, perfecting it in their fifth year. James and Black learned on their own, but Pettigrew needed their help. When transformed, they could safely run with Lupin in the Forbidden Forest. Sirius and James were large enough to keep a Werewolf in check, though there were near misses. Their Animagus forms determined their nicknames; Black was Padfoot, James was Prongs. Pettigrew, the rat, was Wormtail.

Harry asks what animal his father was, but Hermione interrupts, saying it was dangerous to allow a Werewolf to run free. Lupin admits it was, but they were young and uncaring. Lupin regrets never telling Dumbledore that Black is an Animagus, but says he was ashamed to admit to him that he betrayed his trust by once roaming the village as a Werewolf. Lupin believed Black was serving Voldemort and convinced himself that Black used Dark Magic to enter the castle, rather than his Animagus form. He confesses that Snape was partially right, that by remaining silent, he was aiding Black. Black demands to know how Snape is involved, and Lupin explains that Snape is now a Hogwarts teacher. Black once tricked Snape after he became curious about Lupin's monthly disappearances. Black told him about the Whomping Willow and how to get into the tunnel. It was James' last-minute intervention that saved Snape from a deadly Werewolf. Dumbledore had, of course, forbidden Snape from revealing anything about Lupin's condition.

Snape now reveals himself, having been hiding under Harry's Invisibility Cloak which he had found by the Whomping Willow where Harry and Hermione had dropped it. He was bringing Lupin his Wolfsbane potion when he noticed a very interesting map on Lupin's desk that confirmed his suspicion Lupin was helping Black. Snape magically binds Lupin before he can explain, then insists everyone return to the castle so he can have a word with the Dementors. Harry blocks the door, demanding Snape listen. When Snape refuses, Harry disarms him, helped by Ron and, surprisingly, Hermione. Their triple-force spell tosses Snape against the wall and knocks him out.

Harry still doubts Lupin's story. Lupin makes Ron hand over Scabbers, though Ron protests that even if Peter Pettigrew assumes a rat form, why would it be Scabbers? Black explains that when Fudge visited him at Azkaban, he gave Sirius the newspaper containing the Weasley family photograph. Black recognized Pettigrew (as Scabbers) in the photo by his missing toe. Pettigrew severed his finger before killing the Muggles, then, shouting that Black murdered James and Lily for bystanders to hear, Pettigrew blew up the street. Amid the chaos, he transformed, disappearing into the sewer, his severed finger left behind as evidence he was dead. Lupin points out that Scabbers has been in the Weasley family for twelve years, whereas a common rat lives only three or four. Lupin observes that Scabbers is looking unwell, though Ron claims it is stress caused by "that mad cat" going after him all the time. Harry figures differently: Scabbers was already looking ill in Diagon Alley, and before Hermione bought Crookshanks, presumably because he had heard about Black's escape.

Crookshanks recognized Pettigrew for what he was. He had also spotted Black and initially distrusted him, but helped him once he understood what Black's purpose was. Unable to bring Scabbers to Sirius, Crookshanks stole Neville's password list and later told Black that Scabbers had vanished, leaving blood and hairs on Ron's sheets. After all, appearing dead had worked once before.

Just as Black is about to kill Pettigrew, Harry says Black was his parents' Secret-Keeper and he betrayed them. Black claims he was responsible for their deaths, but was not the Secret Keeper; he had persuaded James and Lily to switch Secret-Keepers, using Pettigrew rather than him, believing no one would suspect a weak Wizard like Pettigrew. When Black checked on Pettigrew's hiding place and found him missing without any apparent struggle, he feared something had happened. He went to Godric's Hollow, and finding James and Lily's bodies amid their destroyed house, realized Pettigrew betrayed the Potters to Voldemort.

Lupin calls a halt, and he and Black cast a spell that transforms Scabbers into a human: a short man with vaguely rat-like features, colorless hair, and a large bald spot&mdash;it is Peter Pettigrew. When Lupin demands an explanation about the night James and Lily died, Pettigrew feebly claims he faked his death because he feared Black, after betraying the Potters, would also come after him, and he possessed powers that "He Who Must Not Be Named" taught him. Black responds that Voldemort's followers are unhappy with Pettigrew, that Voldemort went to the Potters' on Pettigrew's information and died there. The Death Eaters in Azkaban think Pettigrew double-crossed Voldemort, and many are still at large. Lupin asks why an innocent man would stay hidden for twelve years. Pettigrew claims he was scared because he put Voldemort's top lieutenant, Sirius Black, in Azkaban. Sirius angrily reminds Pettigrew that he (Pettigrew) was the Potter's Secret-Keeper.

Black states that Pettigrew never harmed Harry because he would never risk acting on Voldemort's behalf unless he knew Voldemort could protect him. Black kept his sanity in Azkaban by changing into a dog when things became unbearable. A dog's simpler thoughts are less affected by the Dementors than a human's. Dementors are blind and were unable to detect him transforming. Instead, they sense and navigate towards emotions. When Black recognized Pettigrew's Animagus form in the photograph, he vowed to expose the traitor. As a dog, he was able to evade the Dementors during his escape. He journeyed north to Hogwarts and lived in the Forbidden Forest, emerging to watch the Quidditch matches.

Harry is finally convinced that Black is innocent. Pettigrew's pleas for mercy are ignored, and he admits to serving the Dark Lord, because he would have been killed if he resisted. Black says he should have died for his friends, as they would have done for him. Lupin and Black prepare to execute Peter, but Harry intervenes to protect his father's two best friends from becoming murderers; Pettigrew will be turned over to the Dementors. Black and Lupin relent, and Lupin binds Pettigrew and splints Ron's leg. Black warns Pettigrew that if he transforms, he will kill him. Lupin charms the unconscious Snape to float along with them. Black suggests having two people chained to Pettigrew to prevent him escaping. Lupin and Ron volunteer, and Black, using Snape's wand, conjures manacles. With Crookshanks leading, they return to the tunnel.

Proceeding down the tunnel, Black realizes he will be a free man once Pettigrew is turned over to the authorities. He tells Harry that he is his godfather and also his guardian and hesitantly offers to have Harry live with him. Harry's enthusiastic, "Yes!" catches Black rather by surprise, and his smile makes him look ten years younger.

As they exit the tunnel, a shifting cloud bathes them in full moonlight. Lupin, who has forgotten to take his potion, transforms into a Werewolf. Black yells at Harry to run, but he cannot&mdash;Ron is still chained to Pettigrew. Black transforms into a dog to defend the others. Lupin, now a Werewolf, is no longer shackled to Pettigrew, who grabs Lupin's dropped wand and stuns Ron and Crookshanks. Harry disarms Pettigrew, but he transforms into a rat and vanishes into the grass. Lupin, blocked by Black from attacking Harry, Hermione, and the Stunned Ron, bounds off into the Forbidden Forest, chased by a wounded Black.

Harry and Hermione rush to Ron's aid, but they are unable to undo Pettigrew's jinx. Hearing a whining yelp, Harry and Hermione run to the lake and find the human Black cowering on the shore. Nearly a hundred Dementors are approaching from all directions. Harry and Hermione leap to Black's defense, but there are too many Dementors, and Harry's Patronus charm is too weak to repel them. The creatures' presence overwhelm Harry and Hermione. Harry falls and feels himself being lifted by one to administer the Kiss.

As Harry's consciousness fades, a bright light seems to race around him, scattering the Dementors. As they disperse, a large glowing animal appears in the light's midst, then trots back to someone standing on the lake's opposite shore. What Harry sees before losing consciousness seems impossible.

Harry awakens in the infirmary and hears Minister for Magic Cornelius Fudge and Professor Snape discussing the night's events. Snape says that the cut on his head was Harry, Ron, and Hermione's work but that they were probably under a Confundus charm put on them by Black. When he regained consciousness, the Dementors were returning to their posts, and he found Harry, Hermione, and Black unconscious beside the lake. He conjured stretchers and brought them to the Hospital Wing. Fudge says this will probably put him in line for the Order of Merlin, Third Class. Harry opens his eyes and sees Hermione in the next bed, wide awake and looking frightened. Nearby, Madam Pomfrey is attending to Ron. Madam Pomfrey tells Harry that Black has been captured, and the Dementors will shortly administer the Kiss. Harry leaps up, shouting that Sirius is innocent and Peter Pettigrew is alive and is an Animagus. Snape says he is obviously Confunded, and Madam Pomfrey forces him back into bed. When Professor Dumbledore arrives, Harry also tells him. Dumbledore says he has spoken with Black and needs to speak to Harry and Hermione alone. Madam Pomfrey and Fudge depart, but Snape protests that Black has shown that he was capable of killing someone when he was 16. Dumbledore responds that he is aware, and Snape leaves stiffly.

Harry and Hermione try to explain what happened, but Dumbledore says their unsupported word will not save Black. Neither can Lupin, even if he were not currently roaming the Forbidden Forest. Apart from his being Black's old friend, a Werewolf's word counts for little. Snape's version will bear the most credibility, and while Dumbledore believes Harry and Hermione, he cannot force other people to see the truth. "What we need," Dumbledore comments, "is more time." Hermione apparently understands, though Harry does not. He mentions that Black is in Professor Flitwick's office. He cryptically says it is five minutes before midnight, that they must not be seen, and that more than one innocent life can be saved. He tells Hermione that "three turns" should do it, then leaves, locking them in the infirmary.

Harry is mystified, but Hermione produces a tiny sparkling hourglass from her robes. She loops the chain around herself and Harry, and turns the hourglass over three times. The world becomes a spinning blur; when it settles, they are standing in the deserted Entrance Hall, and the sun is shining. Pushing them into a broom closet, Hermione tells Harry that they are now three hours in the past. Slow footsteps are heard going past, and Hermione says that it is themselves under the Invisibility Cloak; Harry is trying to comprehend being in two places at the same time, in the closet with Hermione as well as under the Cloak with Ron and Hermione heading for Hagrid's hut. Hermione explains that the hourglass is a Time-Turner; she has been using it all year to get to all her classes. Professor McGonagall instructed her to tell no one about it.

Now that they have gone back three hours, Hermione is unsure what Dumbledore expects them to do. Harry guesses that he intends for them to save Buckbeak and Black, who is locked in Flitwick's office. Buckbeak can fly them to Flitwick's window to save Black. They head for the Forbidden Forest, edging around it until they reach Hagrid's pumpkin patch. There they watch themselves going in the hut. Harry wants to grab Buckbeak, but Hermione says the Committee must see him first, otherwise they will think Hagrid freed him. They hear Hagrid breaking the milk jug and the other Hermione finding Scabbers. Harry wants to dash in and grab Pettigrew, but Hermione asks what would he think if he suddenly saw himself bursting in that way. There is a reason Dumbledore said they must not be seen.

The Committee, including Professor Dumbledore and Cornelius Fudge, approach. Harry and Hermione watch Harry, Ron, and Hermione vanish under the Invisibility Cloak and exit at the back while the Committee enter the front. After the executioner, Macnair, has spotted Buckbeak, Harry decides it is time to act. He bows to Buckbeak and starts leading him into the forest, but Buckbeak resists. As the Committee starts to exit the hut, Dumbledore calls them back, saying that the decree needs another signature. Just as Harry gets Buckbeak into the woods, the Committee emerges to find Buckbeak gone. Macnair slams his axe into the fence in anger.

Harry and Hermione, with Buckbeak, move closer to the Whomping Willow and watch as the black dog drags Ron into the tunnel. Shortly, Crookshanks stills the branches and their other selves go into the tunnel. Almost immediately, Dumbledore, Macnair, Fudge, and the old Committee member walk past on their way back to the castle. Now they see Professor Lupin running to the Whomping Willow and diving into the passage. Harry wonders if he could dash out and collect his Invisibility Cloak, but Hermione dissuades him. Two minutes later, Snape arrives, throws on the Invisibility Cloak, and enters the tunnel.

Now Harry and Hermione must wait while the events inside the Shrieking Shack replay. Hermione wonders how they were saved from all those Dementors. Harry says it must have been a powerful Patronus and believes he saw his late father casting it.

An hour later, everyone exits the tunnel, and Lupin transforms into a Werewolf. Realizing they are standing where Lupin is about to run, Harry and Hermione rapidly retreat to Hagrid's empty hut. Despite a Werewolf roaming loose, Harry wants to see who cast the Patronus and takes off for where the spell-caster was standing. No one is there. Harry suddenly understands: it was not his father he saw, it was himself. As the Dementors attack Black and the earlier Harry and Hermione, he casts the Patronus. A large animal bursts from his wand, and charging the Dementors, scatters them. When they have dispersed, the Patronus, a large silver stag form, canters back to Harry, who now realizes his father's Animagus form was a stag, hence the nickname, "Prongs".

Hermione appears, furious that Harry has been up to something. He explains that his earlier self had seen his later self casting the spell, and he was only performing the events that already happened. They watch as Snape conjures stretchers and transports everyone to the castle. They mount Buckbeak and fly to the West Tower. Hermione charms the window open, and Black climbs out onto Buckbeak. Harry and Hermione dismount on the tower top, and Harry urges Black to leave quickly. Black first inquires about Ron, then escapes with Buckbeak into the night.

Notable Consequences
The main result of the events in the Shrieking Shack is the revelation of the truth surrounding the betrayal of Harry's parents. Harry now knows that Peter Pettigrew is still alive, and had been hiding since his supposed death at Sirius' hand, thirteen years earlier; that it was Pettigrew, not Sirius, that had betrayed his parents; that Sirius, Pettigrew, and Lupin had been friends of his father; and that Sirius, his godfather, still cared about him and would be available to help him. For a short while, Harry believes that he may have a chance to live with Sirius, instead of with the Dursleys. This hope is unfortunately dashed with the escape of Pettigrew, shortly after they leave the Shrieking Shack.

We also learn that Sirius and Pettigrew are Animagi, as Harry's father was; the large black dog that we have seen throughout the book in many cases was Sirius. Pettigrew, of course, had been posing as Ron's rat Scabbers. We don't yet know what shape Harry's father took as an Animagus.

We learn that Snape had been in school at the same time as James, Lupin, Sirius, and Pettigrew, and that he had hated them so much that he is apparently willing to fabricate stories about them in revenge for the past, even to the extent of possibly getting Lupin killed.

Analysis
Clearly, the events in the Shrieking Shack are central to the story of this book, taking up, as they do, almost a quarter of the book. Several things are learned here which may be of interest in the series.

First and foremost, we learn that Sirius is innocent of the crimes for which he has been imprisoned. Readers may find it curious that even wizards have trouble discerning the truth in criminal cases, and we can guess that there will be some discussion of that in later books. We also learn that Lupin is a werewolf, a revelation that has previously been hinted at, and that Sirius is an Animagus, another ability that has been only suggested and never in context with him. We further discover it is Sirius' Animagus ability that allowed him to survive Azkaban relatively unscathed.

Additionally, we learn about Harry's father's school days, and learn that Sirius, Lupin, and Pettigrew were his best friends. We learn that James Potter, Sirius Black, and Peter Pettigrew chose to undertake the extremely difficult Animagus transform to accompany their friend Lupin when he became a werewolf, rather than abandoning him to his own devices. This reinforces Harry's view of his father as a kind, fair, and just person. Harry seems to dismiss the reports of Lupin being allowed to run as a werewolf in Hogsmeade, though as Hermione points out, that was very dangerous and irresponsible.

Snape's hatred of Sirius, and incidentally of James, is explained here as well by revelation of the circumstances alluded to earlier: Dumbledore had mentioned that James saved Snape's life, we now learn how that happened, and perhaps why Snape was unable to forgive him for that. We learn also that Snape believes Lupin had been helping Sirius enter the school, and that both Snape and Lupin, at least initially, believe in Sirius' guilt. Snape must continue to believe Sirius is guilty, in order to prevent his bitter world view from being shattered, so it is necessary that he not see Pettigrew; his being knocked out by the Trio's triple spell is thus a plot requirement. Snape's continuing enmity with Sirius and, to a lesser extent, Lupin may prove necessary in later books.

One point that remains somewhat unexplained is Snape's awareness that the Invisibility Cloak is Harry's. Snape finds it outside the Whomping Willow, and uses it to eavesdrop on Sirius, Black, and the Trio; the door that Ron sees open, that leads him to comment on the Shack being haunted, is, we believe, actually being opened by Snape under the Cloak. It is unclear why Snape immediately guesses the Cloak is Harry's, rather than Ron's or Hermione's. Granted, Harry's family was the most likely to be able to afford one such, but Harry's family are unable to tell Harry that such things even exist, and Hermione's family are Muggles, so despite the Weasley family's relative poverty, Ron is actually the most likely owner. We can't explain this assumption on the part of Snape, no matter how accurate it might be, unless it is extrapolation from the earlier incident outside the Shrieking Shack with Draco Malfoy, Crabbe, and Goyle, possibly coupled with a touch of Legilimency. It is likely that Snape's awareness of the existence of the Cloak, and his awareness also of the Marauder's Map, which he had seen in Harry's possession following that event, will be important later in the series.

Finally, we learn that the Wizarding world has at least some ability to manage, and travel through, time. While the use of the Time-Turner is presented as being somewhat limited, allowing the wearer to go back to an earlier time and thus be in multiple places at the same time, it is entirely possible that Wizarding time-manipulation abilities are much more advanced, and that this specific Time-turner is limited in what it can do, as it has been issued to a student.

Greater Picture
Although the effect of the events in the Shrieking Shack on Sirius is minimal, as he was a fugitive both before and after this episode, it does still leave Harry with an adult who he feels able to call upon in times of need, as Harry will do several times in the next two books. Sirius' being free from Azkaban will allow him to offer the use of his family home in London as the Headquarters of the Order of the Phoenix, something he could not have done had he not re-established contact with Professor Dumbledore. It could be argued that had the events in the Shrieking Shack not occurred, Dumbledore would not have chosen to re-open communications with Sirius, and Sirius in turn would not have been available to help Harry.

Sirius will reveal that the shape James Potter took as an Animagus was that of a stag, similar to the Patronus that Harry casts shortly after the events at the Shrieking Shack. This would be the second corporeal Patronus that Harry had cast; the first, used to disable supposed Dementors at the Quidditch match against Ravenclaw, had quite disturbed Lupin as he recognized its shape, though Harry had been too busy to look at it himself. It will develop that the ability to produce a Patronus is quite advanced defensive magic, usually taught no earlier than sixth year. Harry's facility with this charm will stand him in good stead in his fifth year and later. Possibly Lupin's being able to teach this charm to Harry is a reflection of how good a teacher he is, though given the nature of the curse on that particular teaching position, and the fact that the school seems to be rather scraping the bottom of the barrel to find teachers of Defence Against the Dark Arts, Lupin does not have a lot of competition for excellence. On the other hand, Professor McGonagall seems to consider Lupin a competent teacher, which from McGonagall could be considered high praise indeed.

Dumbledore points out that Harry having stopped Sirius and Lupin from killing Pettigrew leaves Pettigrew owing Harry a life debt. While there is little discussion of life debts in the books, these are apparently taken quite seriously in the Wizarding world. At this time, in response to Harry's bemoaning the fact that, even forewarned, Harry had still let Pettigrew escape to return to the Dark Lord, Dumbledore comments that Voldemort is unlikely to be completely pleased that his lieutenant owes a life debt to his enemy. We will see that Voldemort is not particularly pleased with Pettigrew anyway, treating him as a not particularly valuable servant, rather than as a confidant. In Harry Potter and the Deathly Hallows, we will see that this life debt does end up saving Harry's life and resulting in Pettigrew's death.