Luke has no idea what's happened. He smells like Derek, he says he's Derek, but he's no older than Clary. If he looks at him, really squints and studies his features, he can see the man he's coming to become -- or has already become -- and it's strange to see those features in such a young face. He has no idea what to make of any of this, but then Derek is asking if he knows how to get in touch with his mother and something in Luke's chest tightens until it hurts. This is before life has hurt him, before anything bad has happened to him, and right now the worst thing in his life is that he's woken up here without his family.

And now Luke has no idea what to tell him. He's dealt with magic before and he expects this is some version of that, but he doesn't know why it's happened or how to undo it. Maybe he shouldn't try. Maybe he should just let Derek be a happy, albeit slightly frightened teenager.

"No," he says. "I'm sorry. You... you don't remember this city at all? Or me? None of this is familiar to you?"