Long Ghost by Jesse Jacobson

Ska and Eli, once childhood sweethearts, traveled very different paths after high school. Eli became a decorated Navy SEAL and Ska became a meth addict and a sex slave to her depraved drug dealer. With help, Ska escaped the world of drug use and rebuilt her life. When her dealer is released from prison years later, he comes after Ska, believing her to be responsible for his brother’s death. He vows to rebuild a drug empire on the reservation and kill Ska.
Eli and his friend, Matthew Wolf Steel, have a different plan in mind and the action gets wild as the two SEALS face the dark, violent adversary. During the course of the adventure, Ska and Eli are drawn together, and the sparks fly.