The Cliff House by Chris Brookmyre
Six women travel to Clachan Geal, a remote Scottish island, for a bachelorette party. The women, some old friends, some new acquaintances, are renting out the luxurious mansion on the private island, where it will be just them, a personal chef, and the property manager. The whole thing goes awry quickly. Before dinner but after drinking several cocktails, the chef is discovered dead in the kitchen, clearly murdered, and one of the women is taken, threatened with death by The Reaper. The Reaper claims one of the woman is not who she appears to be, and if she doesn't tell her secret and unless she tells her secret, the hostage will die.
The beginning is a bit slow as we get to know all the women and see the situation from each perspective. I'm not sure if listening to the audio helped keep everything straight or hindered it. It took me a while to really figure out who was who and...