You won't want to leave ... until you can't. Elin Warner receives an invitation from her brother Isaac, with whom she has not spoken to in years, to attend an engagement celebration at an isolated hotel in the Swiss Alps. In the midst of a storm, the hotel, once a sanitarium with a terrible past, is more sinister than welcoming. The morning after his arrival, Isaac discovers that his fiancée, Laure, has disappeared without a trace. Trapped in the eerie hotel, the guests become suspicious of each other and tensions rise. And, without anyone knowing, another woman disappears, and, with her, the key to the danger they are in.