When you're born a light is switched on, a light which shines up through your life. As you get older the light still reaches you, sparkling as it comes up through your memories. And if you're lucky as you travel forward through time, you'll bring the whole of yourself along with you, gathering your skirts and leaving nothing behind, nothing to obscure the light. But if a Bad Thing happens part of you is seared into place, and trapped for ever at that time. The rest of you moves onward, dealing with all the todays and tomorrows, but something, some part of you, is left behind. That part blocks the light, colours the rest of your life, but worse than that, it's alive. Trapped for ever at that moment, and alone in the dark, that part of you is still alive.