Gokudera has gotten complacent.
He's not aware of it on much more than a peripheral level. He knows he takes some things -some people - for granted, and he knows on some vague level that this hasn't worked out well for him in the past. But it's only Yamamoto, after all, and regardless of his experience with unpleasant surprises there can hardly be any dark secrets under the other boy's easy smile and bright eyes. No one who looks that happy could possibly be anything but straightforward, his simple delight in the mere existence Gokudera finds a trial as often as not as much a comfort as it is an irritation.
He's never asked about Yamamoto's history - it's obvious, isn't it, he's been eating sushi and playing baseball and being friends with damn near everyone until the point he decided to become Gokudera's personal shadow, and now the only thing that has changed is that sometimes his baseball bat turns into a sword, and now there's a ring on a chain around his neck. Otherwise Gokudera can trace the framework that is Yamamoto backwards into the past, could sketch out the whole shape of his history until he doesn't need to ask for the backstory sure to be as boring as it is predictable.
So he's not really listening, when Tsuna waxes nostalgic on the way home from school, starts reminiscing about a past Gokudera isn't privy to, praising Yamamoto's performance in some baseball game while Yamamoto laughs gratitude for the compliment. Gokudera isn't paying much attention to the details - it's not like he cares about the game he didn't see, after all, not like he very much enjoys hearing about the life Yamamoto had before they met each other - but then Tsuna says, "I never expected you to take that accident so hard," and Yamamoto says "Ah" with so much sudden strain that Gokudera's attention is brought snapping up, reaction to a tone he's never before heard in the other's voice.
"What?" he asks, and Yamamoto glances back, his eyes wide and shadowed, shoulders hunching with what looks like guilt while Tsuna carries on with blithe unconcern.
"Oh, you know, Gokudera-kun, when Yamamoto broke his arm near the beginning of the school year."
Gokudera can feel his forehead creasing in suspicion, alarm warring with irritation in his thoughts. There's nothing he likes less than being on the outside of a secret, especially with these two, and Yamamoto is still eyeing him with uncharacteristic panic creeping onto his face, like he's afraid of Gokudera's reaction to whatever this is.
"I don't know," Gokudera grates. Tsuna turns, then, drawn around by the tone in the other's voice, but Gokudera doesn't look at him; he's holding Yamamoto's gaze instead, his eyes narrowing into suspicion as Yamamoto looks at him with as much concern as if Gokudera is one of the bombs he carries.
"Oh," Tsuna says, his voice heavy with the dead weight of someone who only sees their misstep as they're falling over the edge. "Haha, well, now you know!" Tsuna's laugh is less convincing than Yamamoto's, awkward and strained so tense usually Gokudera would take the hint and let the topic go, if it were just about Tsuna's comfort. But there's something else here, a shadow in Yamamoto's expression Gokudera can't parse and so:
"What do you mean, 'took it hard'?"
"Uh," Tsuna says, "Gokudera-kun-"
"I was going to jump off the school roof," Yamamoto says, the first words he's spoken since Gokudera's attention focused in on the conversation. For a moment the sound of his voice alone is a comfort, the rhythm and cadence ordinary enough to offset the uncanny emotion in his features. Then the actual meaning sinks in, the disparate sounds forming into a cohesive whole, and Gokudera feels like the air around him has dropped several degrees.
"What," he says, every sound tearing out over his tongue, and Tsuna makes some strangled noise of panic but Gokudera isn't looking away from Yamamoto, is waiting for the laughter to this joke that is in incredibly poor taste. "You were going to what?"
Yamamoto stops walking, turns to face Gokudera fully. His shoulders are softer than usual, slouched out of their usual clean line, his eyes wide and dark and his mouth still free of any trace of amusement. Gokudera takes another half-step to bring him solidly into Yamamoto's personal space before he stops too. Tsuna hesitates a few steps farther on, just in the outside edge of Gokudera's periphery, before making some excuse Gokudera doesn't hear and moving on down the street, out of range of the fallout.
Gokudera doesn't look after him, too focused on the boy in front of him to trail the other. Yamamoto still looks uncommonly calm, cool and sincere like he never does, the usual bubbling undercurrent of delight entirely absent from his features. Gokudera has another chill, this one of foreboding, that maybe-
"I was planning to jump off the school roof," Yamamoto says again, carefully and slowly like maybe Gokudera just missed some of the words the first time around. "I broke my arm. Even if I kept playing in middle school, high school, there's no way I could be a professional player like I wanted to be."
"So what?" Gokudera snaps. His heart is starting to race, his breathing catching desperate in his lungs as if Yamamoto is on the rooftop right now, standing on the edge with an endless fall before him. "So fucking what, so you couldn't play baseball, big fucking deal."
"It was a big deal," Yamamoto says, evenly, like he's not talking about his life, like he's not talking about a near-miss Gokudera never even knew about, never even suspected. "It was all I had."
"Fuck that," Gokudera says, not sure why the words are tearing so raw in his throat. He grabs at Yamamoto's shirt, reaching for the familiarity of the action, but shaking the other offers no comfort at all, not when he feels like all the ground under his feet has vanished to leave him in freefall. "How could you, you would have died."
Yamamoto laughs then, at last, but it's not the sound Gokudera wanted, it's thin and shaky and as terrifyingly fragile as the heartbeat thudding underneath the press of Gokudera's knuckles against Yamamoto's chest. Gokudera glares at Yamamoto but it doesn't seem to help; those eyes are still soft, apologetic and warm and painfully tender, like he's not even seeing the fury burning away the cold in Gokudera's blood.
"That was the idea," he says, and Gokudera shakes him again, roughly enough that Yamamoto moves with the force.
"I can't believe you," and he has to look away, he has to stare at Yamamoto's shirt and not his eyes, he doesn't trust his glare to hold. "You would have died, just like that, and I wouldn't-" He catches himself, chokes the words back. "The Tenth wouldn't have had a Rain Guardian, we would have been missing one."
"Tsuna's the one who saved me," Yamamoto says, careful with the words as if they're a touch, and Gokudera's throat closes off into a knot, endless gratitude for this atop all the other things Tsuna has already done for him.
"You fucking idiot," Gokudera grates, leans in close so he can press his forehead to Yamamoto's collarbone, so he can squeeze his eyes shut and fight back the ache of almost-loss in his throat. "You have other things than baseball to live for."
There's a huff over his head, a laugh that's fainter but warmer than the last. Fingers brush at Gokudera's waist, a touch ghosting over his uniform jacket, lighting into true contact when Gokudera doesn't jerk away.
"Yeah," Yamamoto says, the words coming so close Gokudera can feel their heat at the top of his head, can feel Yamamoto's lips catching at the strands of his hair. "I gotta be around to watch those fireworks, right?"
Gokudera doesn't mean to laugh. The sound just pulls out of him, a burst of amusement that veers uncomfortably close to a sob before he can catch his breath and hold the sound back. But Yamamoto doesn't step away, and this close Gokudera can hear the sound of his heartbeat, a steady rhythm to prove what he does have.
Gokudera can't remember ever feeling lucky before.