Blood Always Tells by Hilary Davidson (Forge hardcover, 15 April 2014).
Dominique Monaghan finds out that her married lover is cheating on both her and his wife, and decides to get even by blackmailing him. Her plan is to confront him when they are at Gary's country home for the weekend, but before she can do it, they are both kidnapped.
The kidnappers load them into the back of a van and drive for a few hours. They end up at an isolated house that looks creepy enough to be haunted. Dominique and Gary are forced inside and shut in separate rooms. But Dominique is nothing if not resourceful, and she manages to steal a cell-phone long enough to call her big brother Desmond.
Desmond is the quintessential Good Guy and spends a lot of time volunteering for Causes. He feels like he's been cleaning up Dominique's messes forever. He happens to be on a date when he talks to his sister, and when he hears her convoluted tale he rushes off to find her.
But what he discovers when he arrives creates more questions than answers, and he ends up on a lengthy quest that involves multiple law enforcement agencies, a couple of shady lawyers, and Gary's wealthy socialite wife.
The plot of this standalone contains many twists, but it's not unwieldy. It's a different type of novel than Davidson's Lily Moore series, but still gripping and suspenseful. You may find yourself reading long into the night rather than put this book down.
FTC Full Disclosure: Many thanks to the author for the Advance Reading Copy.