Every Single Secret by Christina Dodd

Never whisper the truth. Never reveal the past.

In an isolated lighthouse on the California coast, Rowan Winterbourne lives a solitary life with only her secrets for company. For she has a mission that drives her—to avenge herself against Gregory Torval, the powerful drug and arms dealer who murdered her mother and vowed to eliminate everyone in her family.
Then Joe Grantham arrives at her door and, for the first time, Rowan lets her guard down—a dangerous mistake when he blackmails her to go with him to Torval’s private island. There Torval’s decadent birthday celebration rages, and while Joe pursues his own agenda, she’ll provide the perfect distraction.
On Raptor Island, Torval’s will is law and Joe, the closest she has to an ally, is an enigma she can’t trust. One false move, one careless word, and Rowan will die. As dark truths are uncovered, one by one, Rowan recognizes her last chance for the revenge has come. But is it worth everything she must sacrifice to get out alive?