八个好友一同前往一座位于森林中的度假屋，为其中一位即将出国留学的朋友送行。这次旅行对他们来说是一个回顾高中时光的机会。然而，一连串令人不安的事件使得团体开始感到紧张，他们开始怀疑度假屋内某个地方隐藏着第九个人。随着情况越来越危险，他们试图解开谜团，却发现过去的黑暗秘密再次困扰着每个人。他们意识到，为了生存下去，必须尽快找出谁是幕后黑手，策划了这一系列致命而血腥的事件。

Michael Schäffer is among the Westerners whose families are killed in the great tsunami while on holiday at Thailand's Phuket beach. So is Billi Cramer, who is less introvert and hence accepts a Greek international relief force therapist's advice to seek contact with a compatriot in the same position. They got on so well there may be a real relationship in the making, but the grief still weighs heavily.