While a senior in high school, Sabine Burns suffers a devastating loss when her best friend Kris is deliberately killed by a drug overdose forced on her by her former pimp boyfriend. After he taunts Sabine via text-telling her what he has done in revenge for Kris fleeing from him, knowing the authorities will ignore the overdose death of a former underage streetwalker junkie-Sabine bides her time for several years until she finally takes a brutal retribution, condemning Kris's killer to life in a wheelchair. Since that night ten years ago, the CrossFit instructor and martial arts expert honors the memory of her best friend by quietly going out a few nights each week to help the sexually-exploited women who toil in the dark, dangerous streets for unscrupulous men. Casey Christiansen is the MMA and Krav Maga team lead for Armstrong Protection Services, one of the legendary Seven, who is stunned when she sees Sabine in action one night, easily taking down a treacherous arms dealer with her martial arts skills. Fascinated by the beautiful femme who defeated the boastful MMA practitioner with little more thought than she'd give to swatting a fly, Casey is further filled with compassion when she learns about Sabine's painful past from the APS team of Piper Haines and Kelly Armstrong-immediately deciding this sweet, shy woman is hers to love and protect. When APS and Casey find out Sabine has been targeted by a loose association of powerful local pimps-who had been publicly humiliated on the street by her one night when one of them had tried unsuccessfully to force Sabine to earn money for him as a sex worker instead of taking care of street women-they spring into action, vowing they will provide all the protection she needs as she does the work so dear to her heart. But Casey realizes the threat to Sabine is much deeper and insidious than it appears on the surface when street women start to disappear in warning, as the pimps makes it clear the women's lives-and the lives of others whom Sabine cares deeply about-will continue to be forfeit unless she comes to heel so they regain both their reputations and the upper hand. With the stakes this high, Sabine must figure out a way to avoid knuckling under to their demands, to avoid the fate from which she has tried so hard to save other women. Because if she can't, but continues to defy them-Casey Christiansen just might be one of the ones who ends up dead.