Hands.

Their eyes meet from across the room.
It feels like they both just hit a big drop in road going fast.
They walk quickly towards each and their faces light up like signal fires.
"Hey big brother." she says with all warmth in the world.
"Missed you too little sis." he says as he wraps his arm around her shoulder.
They walk out the door arm and arm against the world, as it always was.