The euphoria at Gryffindor finally winning the quidditch cup quickly faded, for exams were approaching quickly. O.W.L. and N.E.W.T students were the busiest, but almost everyone was in varying states of anxiety and sleep deprivation.

The first years weren't quite sure what to do in the face of exams and frequently resorted to studying together in large groups. Abigail had told them all that muggles were always talking about study snacks, and upon hearing this the Hufflepuffs took it upon themselves to visit the kitchens and supply everyone with pastries. They were having a grand old time in an unused classroom, practicing spells and quizzing each other while eating chocolate eclairs.

Christina had asked Harry, Ron, and Hermione about exams. Harry had said not to worry, that professors went easier on first years than older students. Ron had told her that McGonagall and Snape's exams were the ones to watch out for, and Hermione had passed along her old study guide from first year. The study guide was a thick stack of parchment with pages and pages of notes in Hermione's neat handwriting detailing wand movements, potion recipes, and facts about goblin rebellions. Christina had politely thanked Hermione for the study guide and then put it aside because looking at it gave her anxiety.

In the end, though, most of her exams were relatively painless. Professor Flitwick had gone easy on them all, Professor Sprout pronounced them all skilled herbologists, and even Professor Binns' two-hour written exam was not as bad as Christina thought it would be. The potions exam was a grueling two hours in the dungeons, frigid despite the summer heat outside. Professor Snape loomed unpleasantly over them all, peering into their cauldrons and sneering at them as they worked.

Christina's last exam was transfiguration, which had both a written and a practical component. This was the one she was most worried about, since McGonagall was rarely lenient. It was a warm afternoon and the exam room felt stuffy and airless as she sat at a desk trying to remember the wand movements to turn a cockroach into a button. The practical portion was easier. She was able to turn a match into a perfect needle and walked out of the exam feeling drained, but also that she might have done decently well on the exam.

She planned to go down to the kitchens and get a drink, then go back upstairs to change out of her sweat-soaked uniform, but before she could go anywhere she heard pounding footsteps and someone calling her name.

"Christina!" Ron was running towards her, apparently having outstripped Harry and Hermione, who were huffing and puffing behind him. "Christina. I was hoping we'd catch you."

"Where have you lot come from?"

"Divination exam. Well, Harry and me, I don't know where Hermione's been."

"I had my arithmancy exam, Ronald!"

Harry, having finally caught up with Ron, held out a scrap of parchment to her. "It's from Hagrid."

Christina took the note from Harry and read it. "Lost appeal. Executing at sunset. Nothing you can do. Don't come down."

"We're going, of course." said Harry. "At sunset. I'll bring my invisibility cloak so we aren't seen."

"That'll be after dinner." said Hermione. "That gives you a few hours."

Before dinner Christina went upstairs and swapped the black Mary Janes she wore with her uniform for old sneakers. She'd seen the muddy ground outside Hagrid's house and was not taking any chances. All four of them were rather quiet at dinner. Harry, Ron and Hermione were huddled together pretending to debrief the divination final while Christina told Sam about her plans in a whisper.

"You're not actually going." Sam muttered.

"I am. We're going to support Hagrid."

"That's after dark! Sirius Black is still running around! There's dementors and the like."

"Yeah, but I want to go. I've spent too many hours reading about hippogriffs not to support Hagrid now. I'll be careful, I promise. We'll be out and right back in."

They didn't go up to the tower after dinner, instead skulking around the entrance hall until it was deserted before putting on the cloak. Four of them underneath it proved to be a very tight fit, but with Christina being much shorter than the others they just managed it. Ron joked it was lucky Harry hadn't had a secret older brother and Hermione kicked him under the cloak.

Shuffling quietly so as not to rustle the cloak, they squeezed out the front doors and all the way down the lawn to Hagrid's hut. Hagrid's hut was bathed in golden evening light, and for just a few moments it so lovely that it did not betray the horrors that were about to happen. Hermione looked around furtively, then extended one hand outside the cloak to knock on Hagrid's door.

Hagrid's face was streaked with tears as he opened the door. "Harry—Ron—you shouldn't have come. Get inside, it's not safe out here."

Christina sat down awkwardly at the table as Hagrid tried to make tea. This was her first time inside Hagrid's house and it was a terrible occasion for a first visit. She could sense the pure hopelessness in Hagrid, the way it seemed to cling to him and weigh him down, and even he couldn't het excited about welcoming Harry Potter's younger sister to his home.

"Hagrid, where's Buckbeak?" Hermione asked.

"Outside. I thought he could feel the fresh air before—before—" he broke into sobs, the jug in his hands dropping to the floor.

"It's all right, Hagrid." Hermione jumped up. "I'll make the tea."

"It's all Lucius Malfoy's doing." Hagrid sobbed. "He's threatened them, probably. Not even Dumbledore can do anything about it."

Hermione took down an empty milk jug and shrieked in surprise. "Ron! I don't believe it. It's Scabbers!" She overturned the jug and Scabbers slid out onto the table.

"Scabbers! Blimey." Ron held up Scabbers, who looked very ill and whose fur was falling out in large patches. Christina gazed up at the rat, wondering how on earth it wasn't dead yet.

A knock sounded on the door.

"That's them." said Hagrid. "Go, go, you can't seen. If the minister finds out . . ."

Hermione threw the cloak over the four them plus Scabbers as Hagrid herded them out his back door. "Let's go." She whispered. "Let's get away. I can't watch."

"Scabbers!" Ron moaned.

"Ssh!" Hermione sharply shushed him.

"No, quiet! Stay put, Scabbers." They stopped as Ron struggled with the rat, and all of a sudden they heard the swish of the axe.

"They did it." Hermione whispered. "They really did it." They stood transfixed with horror for a few moments, still packed in close quarters under the cloak as the sky darkened above them.

"Ron, what are you doing?" Christina hissed as his elbow narrowly missed her face.

"It's Scabbers! He won't—stay—put! Ow! He bit me! Scabbers, no!"

"It's Crookshanks!" Harry pointed a short way away, where Crookshanks was slinking through the dusk.

"Crookshanks no!" Hermione whispered. "Please, no."

"Scabbers!" Ron threw the cloak off and ran after the rat. Hermione, with only a moment's hesitation, balled up the cloak in her pocket and the others ran after him.

"Crookshanks! No! Get off him, you stupid fur ball!" Ron kicked Crookshanks away and grabbed Scabbers again. "The bloody hell was that about?"

"No!" Harry jolted with horror and the others looked to see that huge jet-black dog bounding toward them. Christina shrieked and ducked but it leapt far over her head, overtaking all of them. Harry stood up and roughly pushed her behind him as the dog came back for another attack. It went not for Harry but for Ron, seizing his arm and dragging him away.

Christina and Harry launched themselves at the dog, pounding its broad flanks and grabbing handfuls of its matted fur, but the dog shook them off easily and bounded away with Ron as if he weighed no more than a newspaper an ordinary dog might carry.

"No!" Harry ran forward, but something smacked the three of them around the heads and knocked them over.

"The whomping willow!" Hermione screamed. The black dog and Ron had already ducked beneath its whirling branches, heading for a large hole at its roots. Christina tried to duck under the branches but one caught her knees, knocking the wind out of her as she fell flat on her stomach. By the time she looked up the dog had already disappeared, Ron's foot hooked around a root as a last stand at saying above ground. With a sickening snap! Ron's leg broke and he was dragged under.

"We've got to go for help!" Hermione gasped, ducking a large branch.

"There's no time!" Harry yelled. "Who knows what that dog can do! We have to go!"

"We can't get in!" Christina yelped as another branch smacked her ribs. All three of them were cut and bleeding, and Christina figured they weren't much use to Ron if they were half-dead.

"We've got to get in!" Harry shouted. "The dog got in, we can too!" A blur of orange darted past Harry as Crookshanks ducked under the branches to press a large knot on the tree's trunk. As if a pause button had been pressed, all the branches froze. "Go, go!" Harry jumped into the hole, Hermione and Christina at his heels. They found themselves in a dark tunnel beneath the tree.

"Lumos. Where does this go?" Hermione asked, looking around.

"I saw it on the Marauder's Map." Harry panted as they scrambled down the tunnel after Crookshanks. "Not sure where it goes, but somewhere towards Hogsmeade."

"What's the Marauder's Map?" Christina asked. She was between Harry and Hermione, clinging to the back of Harry's robes.

"No time to explain." Harry muttered. "It's basically just a map of Hogwarts." The tunnel narrowed and they hunched over more. Walking like this was extremely painful, and just when Christina thought she couldn't bear another second of it, Harry pushed his way up through a narrow trap door. Hermione and Christina followed, finding themselves in an abandoned room.

No, not just abandoned. Someone had actively destroyed this place. Paper was torn from the walls and mysterious stains clung to the floor. The furniture had been smashed and the small chandelier lay on the ground in a thousand pieces.

"I think we're in the Shrieking Shack." Hermione whispered. "Most haunted building in Britain." she added for Christina's benefit.

A creak echoed overhead and they looked up. "Upstairs." Harry muttered. They tiptoed upstairs, extinguishing their wand lights as they approached the only open door on the hallway.

Crookshanks was curled up in the middle of the dusty bed purring and Ron was on the ground clutching his leg. Harry, Hermione, and Christina dashed to his side.

"Ron! Are you ok?"

"Where's the dog?"

"Not a dog." Ron moaned. "It's a trap. Harry, it's him. He's an animagus."

They whirled around. Christina had a vague impression of a man standing in the shadows before Harry grabbed her and pushed her down onto the bed.

"Expeliarmus!" A voice shouted, and Christina's wand flew from her hand. She straightened up in time to see a hand reach out and catch all the their wands. She followed the arm to the body and then the face, and then she knew: the man in the room with them was Sirius Black.