Sirius had realized something was wrong when James didn't answer the door.
A minute passed.
Then two.
Then four.
And then Sirius got worried.
He shoved his shoulder against the door, forcing it open. Inside the open doorway was a body, on the floor, lifeless brown eyes behind round-framed glasses.
Sirius exhaled sharply, eyes going wide. He sunk to his knees, holding James's body to his chest, the head lolling back, foggy glasses slipping down his forehead.
Tears filled his eyes as Sirius pushed the glasses back onto James's nose. The glasses slipped back down, and Sirius pushed them back, like a stubborn child, almost like James wouldn't really be dead as long as his glasses were on his face.
Sirius's head rolled forward, choking back a sob as his hair fell forward, covering him and James. Tears dripped down his cheeks, staining James's orange sweater.
He couldn't breathe, couldn't think past the cold, breathless body in his arms. He pressed a soft kiss to James's forehead.
"I'm sorry..." Sirius whispered to unhearing ears. And that was when he heard it. The distant sobs of an infant, from an upstairs bedroom.
Harry was alive.
Sirius played James's body down gently on the floor and stood, wobbling slightly. He staggered up the stairs, towards the little nursery, follow the sound of a bawling child.
The nursery was a wreck. Or perhaps it only felt that way, with Lily's body, pale and limp. There was a hollowness in those green eyes that Sirius had once associated with intelligence and life. Now they were dead. Cold.
Harry cried from inside the crib. Sirius picked up the child, rocking him slightly.
"I'm sorry," He whispered, hoping Harry would know how much he meant it. Because it was his fault, wasn't it? He let this happen. He should have been secret keeper. He should have kept them safe. He should have kept them from choosing Peter-
Right. Peter.
The rat.
And then? That's when Sirius got angry.
He doesn't remember much after that.
Not until the aurors got there.