Gillyflower, Heliotrope and Hemlock

In another dimension, in a past that didn't quite happen, three friends are forced to flee a world of ashes and death to hunt down the only person able to save them. Will Harry Potter once again be forced to become The Boy Who Saved? Or will he sink into darkness as the atrocities of the other world crush him in despair? Slash; HP/SB. M for later sexual content. Literally AU.