There hasn't, really, been time for apologies between them, for their mutual, and misplaced, suspicions.
Remus has only seen Sirius once, since. At James and Lily's wake, it was not, exactly, a time for words.
(Sirius had punched the wall, knocked over two wreaths, and left another in an explosion of petals, before McGonagall interceded, correcting all the little things Sirius had become, on sight, hysterical about: she'd conjured glasses to place on the empty bridge of James' nose, and ordered a pillow of white flowers, removing one of clashing autumnal orange, to rest by Lily's still-vibrant red hair.
Quietly, with very wet eyes, she'd told Sirius she'd stun him if she had to. Sirius was still, after that, but it was the stillness of a wand held ready to loose an explosion, and although he stood near the front, all the company seemed to sense the blast radius around him and keep it clear. Remus, himself, stayed near the back. But they had, at one point, caught eyes and exchanged nods. He thought that moment might be the most coherent he'd seen Sirius, the whole time of it.)
Remus has not reached out. He supposes it's about equal chance it'll go one way or the other. Either without James- and without Peter too, a loss in some ways worse, for how it reshapes their marauding memories- he and Sirius will drift into a rough acquaintanceship, where they exchange nods amid crowds and look away, pained. Or Sirius will show up, looking for the one friend he has left.
The knock on his door comes just after dawn on November 8th, 1981, and Remus goes to answer it both expecting it to be Sirius and braced for disappointment.
(He'd thought it was Sirius, when the news came, about the Longbottoms – but it was only Sturgis Podmore, there to tell him Sirius had gone after his cousin Bellatrix alone and wound up catching her at the Longbottoms' door; probably would have gotten himself killed, too, if the noise hadn't woken Alice and Frank up, keeping them from being taken unawares.)
Sirius has his hands braced on both sides of Remus' door. Remus exhales, and the tightness in his chest lessens.
"What do you know about breaking up a marriage?" says Sirius, by way of hello.
"Er," says Remus.
"Thought as much." Sirius takes his hands off the door, waving Remus to move aside, and enters Remus' shabby little flat as if he's done so hundreds of times.
He hasn't: Remus hasn't rented this place very long, and through the year of James in hiding they'd grown more and more distant. Sirius does not so much as look around, but throws himself into the nearest chair.
He sits elbows on his knees, hands clasped together in thought, and Remus realizes, contrary to his immediate assumption, Sirius is not drunk. He is wild-eyed and sallow in a way that suggests sleeplessness, to a friend who shared a dorm with him for seven years.
"Dumbledore speak to you? About the sister?"
"Er-"
"Must have done," Sirius says, opening his arms expansively, as if to say, 'no baby here, and you clearly aren't asking'. "Godfather comes second to blood magic, in the scheme of things, it seems. Harry's safer under the sister's roof anywhere in the world, Dumbledore says."
"…Dumbledore is usually right-"
"He offered," says Sirius. His tone is a blunt weapon. "To be Secret Keeper. It was my idea, to… what we did instead. My fault. I convinced James. I convinced Lily. And thought myself terribly clever, the whole time I came up with the plan that killed them."
"Ah," says Remus. He has been aching, aching with the question of why they didn't tell him. Did Lily think– did James think – he knows perfectly well, that Sirius thought it was him, and that's all right, especially given he thought it was Sirius right back, but if Lily and James thought he… He can't ask, wanting too badly to take Sirius' words as an indication he hadn't lost their trust, too.
"I reckoned I'd get your help with the planning, this time," Sirius says. "I've been hanging about the house, the past couple of days, thought I might get in that way. The husband tried to kick me, threw stones, too. He won't do."
It takes Remus a second to catch up. "As a dog," he says. "You were hanging about as Padfoot. And now you want to break up Lily's sister's marriage."
"Harry," Sirius says, "is supposed to be with me, I'm his godfather. Harry needs to be under the sister's roof. It'd be a lot easier, if she didn't already have a pillock of a husband."
Remus suddenly needs to sit down. It is very early, and he's not sure whether or not his best remaining friend is plotting murder. He's also a little uncomfortable to find himself almost happy that, even if it is murder on the table, Sirius has come to plot with him.
"What, exactly," says Remus, "are you proposing?"
Sirius points at him. "That, essentially," he says. "Proposing. Though, first, the seducing."
"Of Lily's sister." Remus is tempted to ask whether Sirius has seen Lily's sister. He has– permanently pursed lips, bitter-glittering eyes– and between her blond hair and expressions, was reminded more of Narcissa Black than Lily... though Lily's sister was not half so pretty. But Sirius must have, if he's been hanging around the house…
"Who else?" says Sirius. "If you mean Lily might not like it… she'd like it less, Harry growing up in that man's house. I can fix that. I'm a lot better-looking than Lily's brother-in-law."
"There is- generally more to a marriage than looks," Remus says. His brain, on a loop, is saying ohmyGodohmyGodohmyGod, but he's always been the best of the group at reining in the hysterics. Especially now that he's sitting down. "There's a child involved- their own child, that is-"
"I'd keep the other kid, too," says Sirius. "What do you think I am?"
There's an awkward beat.
Sirius looks away first. "I have to do something," he says, his fist clenching and unclenching. "I'd like to think I'm above using a love potion–"
"Sirius-"
Sirius waves him off before Remus can become more horrified. "I wouldn't, but– it'll be better if you're keeping me in line."
"Because I've always been so good at that," Remus says, before he can stop himself. Before he realizes he probably has been more successful at keeping Sirius within the realms of legality than anyone else left alive. "What are you thinking of doing, then?"
Sirius, abruptly, resumes his thinking pose. "I don't know."
"Historically," Remus says, "you haven't had a lot of difficulty with women." He's watched enough women's eyes go right past him and latch onto Sirius over the years to know.
"I didn't have to chase them, though," Sirius says, as if that was a given. "Women just seem to– show up, sometimes. I don't know! We watched James do plenty of chasing, with Lily, but that didn't work out until he stopped…"
Remus is about to counter this, as he has definitely seen Sirius flirt, most especially in Muggle bars; he almost says the name Marlene McKinnon and bites his tongue before bringing up another dead friend. Thinking on it, though, he's not sure Sirius has ever had to say more than 'how about it, then?'. Thinking on it, he's pretty sure it was more often whichever girl was in question saying that to Sirius.
"What do you reckon?" Sirius asks Remus, as if he's somehow likely to know more on the subject of successful seduction of married women. Sirius reaches into his jeans pocket, pulling out a stack of letters so thick there's definitely been some 'enchantment of a Muggle artifact on hand'. "I've got Lily's letters, to me, ever since we started writing in sixth year. There's some stuff about her sister, here. I thought that might be a start."
He holds the stack out to Remus. After what feels like a long moment, Remus takes the parchment. When he opens the top letter, the ink on the cared-for letters still so crisp she might have penned it yesterday. His own letter stack from Lily is nowhere so thick as Sirius', but her hand is as familiar to him as his own. As familiar as any of the Marauders' handwriting, still living, somewhere, on their lost map.
Remus, sighing, looks up and meets Sirius' desperate, hopeful eyes. "It's a start," he agrees, thinking, as he has so many times over the years, okay, so we're doing this. As he smooths out the letter on his lap, a thought catches him. The sister, Sirius keeps saying. "Er- you do remember Lily's sister's name, right?"
"Of course. It's Poppy," Sirius says, automatically, and Remus briefly thinks OhMyGod again, before Sirius gives him a wan version of his smile and says, "Don't worry. I know perfectly well it's Prunella."
Remus, sure he's kidding, begins to half-smile back, but as Sirius, tapping the letter parchment, adds, "Prunella Black. Doesn't sound so bad," finds himself breaking into a laugh, if a silent one, for the first time since… since, perhaps, the last time both of them were with James.