Tale of Two Dragons

Zuko doesn't wake up after the Lightning strikes his chest. It's too quick, and he can't siphon its blow. He falls, slowly dying. Slow enough to see his sister fighting Katara. Slow enough to see their battle unfold. When he finally succumbs the last thing he sees is Katara rushing over a second too late, trying futilely to save his life.

The only thing he hears are Azula's screams and cries, as she sits chained to the grate in a sobbing mess. When Zuko finally succumbs to his wounds he hears her cry.

When he wakes he hears her laugh, and it's the laugh of a child.