Fatal Storm by Carrie Vaughn

Cormac and Amelia take a job at a quaint Victorian mountain lodge: keep an eye on the famous psychic there to judge whether the place is haunted. Simple, right? Three problems: the blizzard that snows everyone in for the weekend, the murdered body that shows up in the morning, and the fact that everyone is sure Cormac did it.

So much for the nice mountain getaway.