Dash by Anna del Mar

Dash Dagger has no idea that his future is about to collide with his past.
He’s in the midst of putting together Tracker Team when he discovers that the father of his ex-lover has been murdered and his daughters are next on the kill list. The woman who stole his heart and destroyed his life is at the top of the list. Even though he’s the last person on earth she wants to see, he has to protect her.
Thena Astor is a woman under siege.
She’s just buried her billionaire father. The Astor’s empire is under attack. Her sisters have vanished. The scion she’s dating is pushing her to get married. If all of that is not enough to break an already broken gal, her ex-lover, the only man she’s ever loved, the warrior she holds responsible for her brother’s death, shows up to contest her inheritance. Dash Dagger smashes into her world like a wrecking ball, challenging everything she knew about her father, his fortune, and her family.
It’s a race against time. Dash has learned Thena’s father was murdered. He’s engaged in a frantic race to unravel a plot to eliminate the Astor family. The mysterious enemy responsible for killing the patriarch is now stalking Thena and her sisters. To defend the women and protect Thena, Dash will put his life on the line.
But can Thena forgive him long enough to join forces, find her sisters, and unmask the predator hunting the Astor women before the entire family is wiped off the face of the earth?