Hereafter by C.K. Crigger
Border Patrol agent Lily Turnbow is fighting a terrorist for her life when everything around her dissolves into a maelstrom of light and thunder. Awakening one hundred years in the future, she finds a ruined world in which bands of mutants are at war with normal humans, and discovers she is as changed as her surroundings.
Resurrected into a society only now beginning to recover from the Event that almost wiped out humanity, Lily has become a Cross-up, acquiring powers she never had before. Driven by a bewildering set of circumstances, she uses these powers for the good of the O'Quinn clan, a horse society straight out of the Old West that has, against their better judgement, taken her in.
But with few exceptions, these people are not as appreciative of her help as one might expect. Even after killing one of her "own kind" the O’Quinn’s view her with fear and suspicion. Sent before the clan elders, Lily's alternatives are banishment into a lonely, friendless world where no one trusts anybody, or death.
But Lily isn't willing to die again.