Hero Rising. Heroes of Saturn, #4

Ari Rayner's fresh start in the city is put on hold when her car breaks down on a mountain pass. Her savior is a hooded angel with haunted eyes who gives new meaning to the words "smoldering intensity". Drawn to his strength, she revels in helping him succumb to his illicit fantasies. Just because she's a woman doesn't mean she's afraid to get down and dirty. Bale made a deathbed promise to protect those who cannot protect themselves, a vow he's done a damn fine job of upholding, but the fire burning within Ari beckons him to play in the flames, and the heat they generate brings the house down.
But such brilliance sheds light on past mistakes that Bale must now answer for. With his true nature revealed, Ari uses everything at her disposal-whips, straps and a firm hand-to convince Bale he is not a monster and is worthy of her love.