Remus tried to be subtle.
He waited until the other Marauders were about to climb out of the portrait hole before approaching McGonagall and quickly adding his name to the Christmas sign-up list. He kept his eyes down, refusing to meet her eye, then hurried away after the others.
Peter usually fell out of the portrait hole, even after almost six and a half years, so there was a good chance he hadn't been noticed. Sirius slung an arm over his shoulders the moment he reached them, and James launched into the tale of Potions on Friday when Evans definitely smiled at him.
"… and then she looked away and started mucking around with her cauldron, but she was still smiling. What was that about, Remus?"
Remus almost missed a step.
"What was what about? Evans?"
"No," Sirius replied. "The Christmas sign-up list. What's going on? Aren't you going home?"
"Are your parents all right? Is that why you're staying?" Peter added, eyes wide with concern.
Remus swallowed. It was on the tip of his tongue to say that, yes, his mother was sick, so it would be easier for him to stay at Hogwarts this Christmas while Dad took care of her. That's what he would be telling everyone else, after all.
Instead, he stopped walking abruptly. Unfortunately, Sirius didn't, which meant that they both teetered precariously for a second, caught off balance, before crashing to the floor.
James and Peter, a few paces ahead of them, turned and stared, before James burst out laughing.
"Merlin's Beard, Moony!" Sirius complained after a stunned second. "I think I might have cracked a rib."
He glared balefully at James, who was still laughing.
"It's the full moon."
The words came out before he could stop them. Sirius immediately stopped struggling to free himself from his tangled robes, and James quietened immediately. He and Peter crouched down next to them.
"What did you say?" Sirius whispered.
Remus swallowed. He was suddenly glad he was on the ground. All he wanted to do was curl up in a little ball.
It was stupid. After all this time, it was stupid.
But he couldn't help feeling a sour curling of shame in his stomach.
Never mind that they were all his closest friends in the world. Never mind that they spent nine full moons of the year with him.
Because, really, it was just a game for them, wasn't it? They ran around with him, breaking the school rules one night a month, being illegal. They risked their lives, not to mention all the trouble they could get into if they were found out.
But they didn't have to. They could give it up at any time. They weren't bound to it like he was. He didn't get to skip a full moon.
And somehow, telling them this was like that stomach-curdling conversation when James and Sirius first mentioned the word "werewolf."
He took a deep breath and tried again. "It's a full moon. On Christmas Eve. So I'm staying here. It's easier, you know, with the shack."
He couldn't look at them. "It's called a Cold Moon. They're really rare at Christmas! They only happen every thirty years or so. They say the next one won't be until 2015. The next millennium!" He was babbling, but they let him.
Then Sirius' arm was back around his shoulder, and James and Peter were helping them both to their feet.
And then they were walking again.
"You know," Sirius announced. "I think Mary Macdonald was checking me out in Defence the other day. Now, there's a fine looking witch."
James snorted. "She was looking at you because you almost set her hair on fire, Padfoot. That's nothing to boast about."
"Oi!"
And everything was back to normal. It was rather anticlimactic.
Remus tried to force himself to relax. He was relieved they weren't talking about it. Of course he was. It was very kind of them to avoid the topic.
He blinked hard.
That was when he noticed the painting of Frederick the Foul, and realised they had reached the staircase to the seventh floor.
Sirius must have felt him tense, since he practically dragged him up the stairs.
And there was the portrait of the Fat Lady, and Sirius and James were still bickering, while Peter supplied the password, and they were all clambering through the hole.
McGonagall was still there, waiting as the sixth year prefect signed it. She watched their arrival with a raised eyebrow.
It continued to rise into her hair line as James charged towards her and snatched the list out of the prefect's hands.
While they all watched, he signed it with a dramatic flourish and thrust it at Sirius, who did the same, followed by Peter.
"Hogwarts at Christmas! I can't wait!" James declared as they all headed back towards the Great Hall for lunch.
That Christmas at Hogwarts a wolf, a stag, a dog and a rat romped in the snow at the edge of the Forbidden Forest.
The sky was bright as the moon overflowed with light.