[It's the mention of Callaghan that causes Hiro to draw in a sharp breath. It's still a very heavy and uncomfortable subject for the two of them, and it's for that reason he doesn't say anything. He keeps his eyes on Tadashi and shrinks back into the couch, though he motions with a hand for Tadashi to continue. "Why did she ask about Callaghan? What did she tell you about us?"]
no subject