Sirius buys the bike in Hogsmeade. Goes alone to do it, sneaks back smelling of petrol, cigarette smoke and engine oil, a few hundred galleons lighter. He can't seem to stop smiling; his feet barely touch the ground as he sneaks back into the dorm. James and Peter are asleep when he gets in—he can hear them snoring as he tiptoes back. Remus, though, he's awake, a faint light glowing through the curtains of his bed. "Moony, c'mere," he whispers. It's cold outside; there's a frost already, and he could see his footprints as he sneaked back over the lawn. If he were a better man, a better friend, he'd feel bad about dragging Remus out of bed. Good thing he isn't.
The curtains twitch back on Remus's bed. He's in his pyjamas. They're striped, flannel. He had a growth spurt in September, so his wrists and ankles show, bony and delicate beneath the hem. Sirius meets Remus's gaze with his most innocent impression, resists the urge to shuffle his feet on the carpet. Remus is trying not to smile; Sirius knows that quirk of his lips so, so well. Remus keeps his wild streak hidden, stays meek as a lamb, keeps the part of him Sirius loves the most a secret, known only to a few. Remus would howl at the moon, even if he wasn't a werewolf. "Get your coat on, got something to show you," he whispers, voice no more than a breath in the hush of the dormitory. "And your shoes."
And Remus, God love him, slips on his shoes without question, follows Sirius down passages only they know until they come out into the chill night next to Hagrid's hut, their breath dragonsmoking in the air.
He wanted to show Remus first, for reasons he doesn't fully understand.
The bike gleams in the moonlight. She's hunkered down low, like an animal about to pounce, all sleek lines and shadows. She's potential, freedom.
"You're going to get into so much trouble," Remus says, but his eyes are glowing as he looks over her, hand outstretched.
"She's worth it," Sirius says, because some things are.
"Like a ship," he says, slinging an arm around Remus's shoulders. Remus is warmer than a human would be. Fevers run faster through him; he eats faster, lives faster. It makes Sirius want to hold on to him sometimes, to slow him down. "She runs like a dream—I'll be a ton-up boy," he says. Remus snorts.
"About ten years too late," he murmurs. "My da used to have a bike like this."
"Not exactly like this, " Sirius tells him. "She's one of a kind." He feels light as air; his feet still don't touch the ground.
They hide her in the shed next to Flitwick's gin distillery, cover her in old potato sacks. Sirius gets three more Howlers from his mother about his desertion of the Black name, his dereliction of duty. He lets every one of them ring out in the Great Hall, sits in his chair, still as a statue as people around him pretend it isn't happening, and Reg looks down at the table in Slytherin, his shoulders hunched in on themselves. He ran away, and is never coming back. The fourth Howler, Remus charms so it sings Champion the Wonder Horse, a programme that Peter is obsessed with. The fifth, he sets on fire with a flame that burns black, letting out a scent so acrid that they have to clear the whole hall.
Slughorn tries to be kind to him in the next lesson. Sirius ignores it, spends the whole of Potions charming Snivellus's flame to burn slightly too high for the potion they're making. Remus doesn't tell him off for it once. Sirius keeps seeing his face as he set it on fire, the quiet anger through every line of his body. All that, for him. It's like pressing down on a bruise. He doesn't mind the Howlers. Let her send them. He's never coming back.
That night, he takes the bike out. Hedges flash past either side of him, lit by his headlight, a green, shadowed blur. He doesn't wear a helmet. When he gets back, his legs are shaking from the rutted tracks, and his hands are numb and cold. Remus, James and Peter are waiting for him outside the shed, their hands tucked in their pockets, scarves wound around their necks. Peter is wearing earmuffs, mismatched gloves. He hates the cold, came out and waited anyway.
"You're an idiot," is all James says to him. They start to walk back into the dorms in silence. Halfway down the corridor, he mutters "it's not even as good as a broom. Can't even fly."
They work out the plans as Remus lies in the hospital wing after a particularly rough moon. Somehow, James had managed to charm one of the old Cleansweeps from Hooch. The bike is an open secret by now—Flitwick found it when he was drunk on elderberry gin, and McGonagall knows everything about everything—so they don't bother to hide what they're doing, although Sirius knows a flying motorbike is not really within the bounds of the school rules. There are about four layers of charms on the bike, although the fourth layer is a speed limiter that Sirius and James are quietly not including in the mapping. Peter wants it to shoot flames from the exhaust, James wants it to be able to skywrite. Sirius just wants to fly.
Remus nibbles on chocolate. He had run from them, in the forest. Sirius had tracked him over streams and gorges, into the darkest parts of the woods where even the spiders feared to go, beyond where Prongs could follow, too fast for Wormtail to run after them. Sirius had run him down, halfway up the mountain, barking him into submission, with nothing but thoughts of pack, more dog than man. A rough moon, but lying out there under the cold light of the stars, waiting for the dawn, something in Sirius had gone quiet and still, contented in a way he hasn't been since he was a child.
"It should go invisible below a certain height," Remus says, snagging a piece of parchment from James. "See here, if we add it to the first layer."
Peter adds some flames to the sketch with a shrug. "Might as well," he says.
There is a tradition of jumping into the lake on the first of February. Peter goes first, divebombing through the thin layer of ice with a whoop that turns into a scream when he hits the water. James carefully places his glasses onto the rock, stands in his trunks, shivering slightly in the chill air. He puffs his chest out, swings his arms back and forth, just in case Lily's watching. The sky is a bright, cold blue. Slytherin are practicing Quidditch in the distance; he can hear Avery shouting at Nott as they go through the Quaffle drills. James is listening too, which is why he doesn't notice Sirius and Remus sneaking up behind him until he's tackled into the water, the three of them a tangle of limbs as they plunge into the icy-cold water of the lake. James's yells are swallowed up by the water. Sirius can feel Remus laughing as they swim up to the surface, his skin warm and smooth between the scars.
It's freezing, in a way that seems to grip his heart. His skin stings with it as he gasps for breath. "This is a bloody stupid idea," Peter says between chattering teeth.
"And yet," Remus says, then swims off, the muscles in his back flexing as he does a few yards of breaststroke. He moves with the economy of a predator, even in the water. Sirius can't quite bring himself to look away.
They get detention for three evenings that week. Sirius can't quite bring himself to regret it. They spend it going over the charmwork for the bike.
It takes them the whole of Saturday to get the charms to stick. In the end, Flitwick comes out and helps them, noting down some of the combinations of charms that they use. Dumbledore appears close to the end of the project, floating a teatray ahead of him. "The flames should go in the second layer," he tells them, then gives them all Earl Grey tea spiked with what may or may not be gin. Remus swears under his breath and adjusts three of the other spells to compensate.
The bike looks more somehow. More wizard than muggle now, definitely. Sirius strokes down her flank, lets his thumb brush the leather of her seat. "Ready, girl?" he murmurs, ignoring Peter's snort.
By the time they've finished, it's dark. Dumbledore and Flitwick have created a roof to keep the rain off, light to see by. Each of them adds something to the work, until it's a patchwork of their different styles. Flitwick even adds some charms of his own, to make the flames shoot from the exhaust, which makes Peter so happy he has to sit down for a moment.
"It's done," James says at last, brushing his hair back from his forehead. "She's ready. Just a night to let the charms settle in, like we did with the m—with another unrelated project," he says hastily, suddenly remembering the professors. They troop in, giddy from the gin and the work. Nothing, not even a Howler, could ruin today for him.
Remus rides pillion for the first test. He's wearing a helmet his da sent him last week, his hair curling out from the bottom of it, over the collar of his coat. He's a warm presence against Sirius's back, arms strong around his middle. Remus has to know how he feels. Has to; it's not as if he's been terribly subtle about it. Sirius has never found the words for how much more real everything feels when Remus is around, how much more of a person he feels like, not a jumbled mess of impulses and yearnings. He doesn't think there are words for it, so he starts the bike, pushes the kickstand up and opens her up so that the sounds echo against the castle walls. James and Peter both cheer as she gains speed, their voices swallowed up by her roar.
They're gaining height steadily as she goes, up to the first floor classrooms, then, up to the Quidditch hoops, the astronomy tower and then they're free, out into open sky, the whole world ahead of them, Remus holding on with a steady grip as the wind whips past their faces, filling their ears with a shrieking whistle. The charms don't falter. They'll take on the world one day, just the four of them. "I love you," he yells, doesn't know if Remus hears. "I love you," he repeats, just for himself. Remus holds on, doesn't let go.