Harry was dragging his feet through the hallway on the way to Defense Against the Dark Arts. Halloween night—as usual—had been overly exciting. After the yearly feast, the Slytherins had scarcely returned to their dormitories when they were again summoned to the Great Hall. Apparently, Sirius Black had entered the castle and attempted to enter the Gryffindor common room, slashing the Fat Lady's portrait when she refused to allow him to enter. Harry had beenfurious—his invisibility cape was locked in his trunk in his dormitory, and he had no way of getting to it. He had gotten stuck in the Great Hall with all the other students, even though his chance to avenge his parents' deaths was so close at hand.

It took hours to get to sleep in the Great Hall, as speculation and rumors were far too exciting. The whirlwind of gossip continued into the next day, following Harry wherever he went.

"What I don't understand," Pansy said to Harry, "is why Sirius Black would attack the Gryffindor common room. You're in Slytherin."

"My mum and dad were in Gryffindor," Harry said. "Black probably figures I'm a Gryffindor legacy."

"You keep forgetting that you're famous, Harry. Everybody knows you're in Slytherin."

"But he's been in Azkaban for years. It's not like he has a roster of the members of each House."

Pansy and Harry continued to debate the point as they walked into the Defense classroom. Sitting at the teacher's desk was Professor Snape.

"Ms. Parkinson, Mr. Potter. Please take your seats."

Harry and Pansy sat down, exchanging perplexed looks. Where was Professor Lupin? Professor Snape answered their unspoken question at the beginning of the lesson.

"Professor Lupin is ill," Snape said. "You may have noticed his condition has been deteriorating, but his recovery is anticipated within the next three days. I will teach in his stead." Professor Snape glanced down at a parchment on the teacher's desk. "I have reviewed a record of the topics you have covered thus far. I find these topics to be less than taxing."

Again, Harry and Pansy exchanged perplexed looks. Professor Lupin was easily the best of their three Defense teachers.

"Even first year students should be able to handle Red Caps and grindylows," Snape said. "This sort of coddling will only make you weak. This class is capable of completing far more challenging work. I expect greater from Slytherin house." Crabbe and Goyle groaned loudly, which Snape ignored. "Open your books to page 394. Today we will be covering werewolves."

Snape looked around the room. "Miss Bullistrode. How would one distinguish between a true wolf and a werewolf?"

"Their snouts are different, sir?" Millicent was clearly unsure of her answer.

Snape nodded. "Correct. The snout of a true wolf is proportionally longer than that of a werewolf. A werewolf's snout may be longer in an absolute sense, but it is smaller in relation to the rest of its body. However, when you are being mauled by a slavering beast, it is unlikely that you will find time to analyze the comparative length of its muzzle. Mr. Potter, tell us another, more useful, distinguishing feature."

"Werewolves are larger, usually," Harry said.

"Usually, Mr. Potter? I asked for something useful."

Harry was desperate to justify his answer. "Some true wolves may be larger than werewolves, but an abnormally large wolf stands a strong chance of being a werewolf."

"Indeed. A werewolf's size in wolf form is roughly proportional to beast's human form. This is most noticeable with children, who transform into atypically small werewolves. Size is an indicator, but not a dispositive characteristic. Again, when you are finding yourself being mauled by an unexpectedly small werewolf, you will not find comfort in knowing that you would usually have been right."

Snape turned and walked toward the blackboard. He spoke with a sigh in his voice. "Miss Davis. Please give me something of substance."

"Werewolves are solitary," said Tracey, "but true wolves are pack animals."

"Five points to Slytherin. The presence of other wolves, or the lack thereof, is the earliest warning sign that you may have encountered a werewolf. Werewolves are not social—they are outcasts among all societies, human and wolf alike. A true wolf will not abide the presence of a transformed werewolf. Moreover, true wolves are pack animals, and a lone wolf will not survive for any length of time. Any time that you encounter a single wolf with no sign of another, you should be prepared to battle a werewolf."

Snape began writing on the blackboard. "Read from page 394. Take detailed notes. You will each prepare an essay, to be submitted to me, on methods of recognizing, defeating, and ultimately killing werewolves. Two rolls of parchment, due Monday."

At the end of class, Harry approached Professor Snape. He had been planning all term to ask Professor Snape to sign his Hogsmeade permission form. (Harry's Uncle Vernon and Aunt Petunia had been rather reluctant to sign anything that would allow Harry to have fun.) Harry had carefully timed his request—in the week before the Slytherin/Gryffindor quidditch match and Snape's house pride would be at its highest, as would be Snape's desire to contrast himself to the perpetually proper Professor McGonnegal. But after Sirius Black's attack the previous night, Harry feared that he may have missed his opportunity.

"Er, Professor Snape?"

Snape looked up from the papers he was grading. "Yes, Mr. Potter? Do you have any revelations regarding werewolves that you wish to discuss with me?"

"No, sir."

"Diappointing. Perhaps later." Snape looked down at his papers and resumed his grading. "What do you want?"

"Professor, this weekend is the first Hogsmeade weekend. My Aunt and Uncle refused to sign my permission form…"

"This does not surprise me," Snape said without looking up.

"I was wondering if you would sign it for me, Professor Snape."

"Your permission form may only be signed by your guardian. I am no more a member of your mother's family than I am a Gryffindor, Mr. Potter." Snape's words were clipped and he fairly spat Harry's last name. As he spoke, his quill strokes grew more dramatic. "Do you think you deserve special treatment? Do you expect me to be mesmerized by your celebrity? I assure you, I am not."

Harry glanced down, hurt by Snape's words. Nobody would ever call Harry's head of house 'kind' or 'affectionate,' but Snape was extremely protective of his Slytherin students. The cutting denial was unexpected.

Snape seemed to sense Harry's change in mood. He looked up from his grading and his tone softened… slightly. "I will not be convinced to sign your permission slip merely because it would to make you happy. We are Slytherins, Potter, not Hufflepuffs. Considering the events of last evening, a trip to Hogsmeade would be ill-advised. You would be extremely vulnerable." Snape paused for a moment. "I assume that you are aware of Sirius Black's connection to your family?"

Harry nodded. "Mrs. Malfoy told me this summer."

"So you understand the need for caution."

"Yes, sir."

"Good." Snape paused. "Is there anything else?"

"No, sir."

"You are dismissed, then." Snape scratched a quick note on a piece of parchment. "If you are late for your next class, here is your pass."

*!*!*!*!*

Harry tossed and turned in his bed, bright light from the full moon streaming through the window. Something was bothering him, refusing to let him sleep. Harry was disappointed that Snape hadn't signed his Hogsmeade permission form, but Harry hadn't really expected to succeed, either. Harry had resigned himself to the fact that he wasn't going to Hogsmeade.

Whatever was bothering him was something else. It was like motion in the corner of his eye—every time he tried to focus on it, it was gone. Or like a picture where there were ten things wrong, and Harry had found nine. He couldn't see the tenth, even though he knew it was there, staring him in the face. And on top of it all, the moonlight was so bright that he couldn't sleep…

Harry sat bolt upright in bed. That was it.

In a flash, Harry had thrown on his invisibility cloak and snuck down to the common room. It was more than two hours past curfew, but Harry couldn't wait. He had to know. He quietly let himself into the hallway and crept to the library.

Inside the library, Harry moved directly to the reference section. He ran his hands along the bindings of the books, looking for the Magical Creatures subsection. Once he arrived, though, he found a void between "Wendigo" and "Wurm." Somebody had removed all the books on werewolves from the library.

And Harry had a good idea who it was.

The next afternoon, Harry returned to the library. At a table in the back, surrounded by no fewer than seven open books, was Hermione Granger. She was leaning into the book she was reading, so close that her nose almost touched. The quill in her hand jerked furiously as she scrawled notes onto a piece of parchment. Harry took a seat at her table, but the bushy-haired Gryffindor didn't look up from her book.

"Granger."

Hermione jumped, startled by Harry's voice.

"Oh, Harry, I didn't see you come in."

"I know. What are you working on?"

"Professor Snape's werewolf essay," said Hermione.

"What do you think of it?" asked Harry.

Hermione cast her eyes to one side. "It's extremely interesting."

"I know!" said Harry. "For example, did you know that lycanthropy symptoms are remarkably similar to influenza?"

"Hmm, that's interesting."

"And lycanthropy is hardly dangerous, any longer, as long as the werewolf has access to the wolfsbane potion."

"Oh?" Hermione began pulling at her hair. "I hadn't really thought…"

"The only problem is that it takes a potion master to brew. Somebody like Professor Snape."

"I guess that limits distribution…" Hermione was obviously nervous now, squirming in her seat, refusing to make eye contact with Harry.

"Wolfsbane potion controls lycanthropy so well that a werewolf could live safely in almost any community." Harry paused. "For example, a school."

Hermione let out a great sigh and suddenly relaxed. "Well, as long as you know already. When did you figure it out?"

"Last night," said Harry. "I couldn't sleep because the moon was so bright. I snuck down to the library to double-check, but somebody had checked out all the werewolf books already."

Hermione blushed slightly. "I didn't intend to check them all out. I was just going to use them in the library, but then I realized why Professor Lupin was absent from class. So I took everything back to Gryffindor. I was reading until almost 3:00 AM."

"Well, what do you think?"

"I think lycanthrope is a terrible condition and the wizards who suffer from it are unfairly persecuted. They're only dangerous once per month, and the danger can be mitigated with the wolfsbane potion. The prejudice that still exists is a holdover from times when werewolves were completely out of control; it's old-fashioned and wrong." Hermione paused. "What about you?"

"Personally, I think Dumbledore is a lunatic for letting Lupin into a school full of children."

Hermione lightly hit Harry on the bicep with the back of her hand. "This is serious business, Harry! You shouldn't be making puns."

"Joking would be absolute lunacy."

Hermione hit Harry on the arm again, much harder. "You're as bad as the Weasley twins."

Harry laughed. "Seriously, though. Dumbledore wouldn't have hired Lupin if he were going to be a problem."

"So, we keep this quiet?" Granger asked.

"I think so," Harry said.

"Good. Because he's the best Defense teacher we've ever had and I'm learning loads from him. Did you get to face the boggart? Mine was Professor McGonagall, telling me that I wouldn't be allowed to sit for my O.W.L.S. because my grades were too good so I had obviously been cheating."

"How'd you defeat that?"

"I imagined the most unlikely teacher possible begging me to return to school, crawling on the ground, telling me I was the smartest witch in a generation and that he was nothing compared to me."

"Professor Snape?"

"No. Gilderoy Lockhart."

Harry burst out laughing. "The seven-time winner of Witch Weekly's Most Charming Smile Award, admitting that he isn't the greatest wizard in England? That is ridiculous."

The two students broke into peals of laughter.