AN: It always bothered me that JK Rowling never once wrote of anyone mourning James and Lily Potter during Harry's time at Hogwarts, despite their importance in both the fall of Voldemort and in Harry's life. Harry passes his Halloweens as if they are normal days, not the anniversaries of his beloved parents' deaths. I figure if anyone was to remember the date as more than Halloween, it would be Snape or Lupin, but even their feelings on these days are never mentioned. (Rowling mentions Harry noticing Snape repeatedly glancing at Lupin during the Halloween feast in his third year, but implies that he chalks it up to Snape acting suspicious about the wolfsbane potion. Other than that, Halloween at Hogwarts is an indistinguishable holiday.)
Therefore, this story takes place in the time between the Halloween feast and Sirius Black's attack of the Fat Lady during Harry's third year at Hogwarts. Small liberties have been taken with Lupin's mood and presence at the feast, so don't fuss if you think it's straying from canon. It just doesn't make sense to me that Lupin would be jovial on the anniversary of a day that pretty much ruined his life.
As always, I do not own Harry Potter or anything related to the franchise. The rights and respect belong to the lovely Ms. Rowling.
...
Minerva McGonagall frowned in thought as she walked briskly from the dwindling Halloween feast in the Great Hall to the teacher's lounge on the sixth floor. Keeping the student population of Hogwarts healthy and safe was becoming an increasingly difficult task. In the past two years alone, the school had seen a rogue troll, the death of a teacher, and the kidnapping of a student, not to mention the countless accidents and close-calls normally associated with teaching a large group of inexperienced witches and wizards. Now, with Sirius Black on the loose, the students lived with a level of danger not known since before the fall of Lord Voldemort. McGonagall allowed her frown to deepen. Even the headmaster, to those who knew him best, appeared a little distraught by recent events. The twinkle in his eye was harder to find these days, and if she wasn't mistaken, it had been completely absent for the entirety of the day. She sighed, sad over the unsatisfying state of current affairs but anticipating the comforting cup of tea waiting for her in the lounge. Just one more winding staircase, a right turn, and a muttered password, and she was there.
She opened the door and felt a small, ironic smile tug at her lips. It looked as if a fellow professor had once again dragged Severus Snape into the teacher's lounge. On this occasion, judging by her part in a decidedly one-sided conversation, it was Sprout who had chosen to be oblivious of Snape's annoyed glare and obvious lack of desire to fraternize with other members of the staff. As McGonagall took a seat, she watched Snape scowl into his full teacup, clearly more interested in the rising steam than in whatever Sprout was saying. The rest of the cozy room was otherwise half-filled with faculty members who were taking advantage of the lounge's squishy armchairs and roaring fire. She heard Flitwick's high-pitched voice behind her,
"What a great feast! Did you enjoy it, Minerva?" he asked.
"I did," she answered, "and the ghosts put on an entertaining show this year."
"Too true! But I noticed Professor Lupin leave us. I hope the poor man is feeling alright; it's not like him to skip out early on a perfectly good feast."
McGonagall thought about it for a moment and came to the same realization: Lupin had left early. Strange, she thought, considering the full moon was still a few nights away. Since Lupin had drunk the wolfsbane potion earlier that afternoon, nothing should have kept the man from attending the entirety of the celebration.
"You're right Filius," she replied. "I wonder what happened." She furrowed her brow, trying to remember if he had mentioned visiting family or contracting a cold, anything that would have detracted him from a hearty, and frankly well-needed, meal. She was about to voice her musings aloud when she heard a voice mutter from across the room.
"It's Halloween," Snape mumbled quietly. McGonagall turned toward the sound, noticing that almost everyone else in the room had done likewise. Their expressions showed slight surprise that for once Snape was contributing to small-talk.
McGonagall leaned in, "Excuse me, I didn't quite catch that."
"It's Halloween," Snape said again in reply, his nose still in his tea, "It's October 31st."
Some of the faculty looked confused, and McGonagall herself needed a moment to consider the date's meaning. Then she understood. It as Halloween, and the anniversary of the fall of Lord Voldemort, but in addition it was the anniversary of the deaths of Lily and James Potter. She saw comprehension dawn on many of the teachers' faces.
"Someone should go find him," she said, "he's probably in his office."
Snape left without a word, his black robes swishing behind him and a neutrally grim expression plastered on his thin, white face.
...
Snape tried not to think as he made his way to Lupin's office. He knew exactly what Lupin was doing there: drinking himself into a blissful stupor. The stupid werewolf was going to get himself killed, and as much as that would please Snape, it would be harder to prove Lupin was abetting Black if he was dead. Still, Snape sneered at Lupin's method of dealing with his grief. If shutting himself away could make him forget, Snape would never leave his office. What he wouldn't give to be able to forget Lily.
Snape halted for just a moment, a look of extreme anguish hidden by his curtain of black hair. She was dead. The most beautiful creature Snape had ever known was dead, and he had not saved her.
He shook himself slightly and continued walking through the empty corridor.
Stupid werewolf. Stupid, ugly, disgraceful werewolf.
When Snape got to Lupin's door, he pounded on it a few times before trying the handle. The door was open, but Snape received no invitation to come in. Instead, he heard a voice from the back of the office moan,
"Go away."
Snape peered through the twilight darkness of the room and found Lupin exactly as he had predicted; sitting at his desk with his head in his hands, an almost empty bottle of Irish whiskey in front of him. Three glasses had been filled and were placed at the opposite side of the desk, as if Lupin were waiting for company, or drinking with the ghosts of his dead friends.
"Please go away," Lupin repeated, his voice muffled by his arms.
"No," Snape snapped, "Get up."
"Why? This is my office and I'll do what I want," Lupin wearily argued. He finally lifted his head from the table, and Snape saw how haggard he looked. His face was blotchy and grey; he had been crying.
Snape felt a twinge of disgust couple with his own sadness, but he did not relent.
"Just get up, before you poison yourself. Your absence has been noticed by more than one member of the staff, and if you don't want to be put on academic suspension, you'll clean yourself up and sleep in your quarters," Snape ordered, not trying to hide the sneer in his voice. He approached Lupin and grabbed the arm nearest him. Lupin was either too apathetic or too drunk to resist being pulled out of the desk chair. Snape allowed the werewolf to throw an arm around his shoulders, providing only just enough physical contact to keep Lupin from falling down.
"Why are you doing this?" Lupin asked. Snape didn't answer, just pursed his lips and started to walk Lupin to the doorway. The weakened man caught a glimpse of the whiskey-filled glasses and stopped short. Snape recognized the pained look on Lupin's face; he had felt it on his own many times.
"They're dead, Severus. They're dead and I didn't save them," he whispered.
Snape's eyes grew a little wider, surprised at the familiarity of the sentiment, but Lupin didn't notice. He was still looking longingly at the glasses. Snape schooled his features once again.
"I know," he said, and pulled Lupin away from the desk.
"Why are you doing this for me?" Lupin asked again.
"I want to prove you're a treasonous accomplice to a mass murderer, and I can't do that if you kill yourself," Snape quipped.
"That isn't why you're helping me," Lupin insisted, "Why are you really doing this?"
Once again, Snape didn't answer. Lupin gave up and focused on putting one foot in front of the other.
They exited the office and headed for the end of the hall. Neither man spoke during the trip to Lupin's sleeping quarters and upon arrival, Snape dumped Lupin unceremoniously onto his bed before swiftly leaving.
Lupin would not remember being brought to his room when he awoke a few hours later. With all the bustle surrounding the attack of the Fat Lady, no one else would, either.