一个大学女生参加姐妹会竞选，而她养了一只可爱的树懒，意识到可以让这只小动物担任姐妹会的吉祥物，对自己拉票也有利。但此后，姐妹会里发生了一系列死亡事件，树懒竟成为了第一嫌疑犯……该片变成了一个姐妹们与树懒斗争的逃生故事，但是，当然，树懒们跑得可不快。

Angry and upset after a sudden breakup with her fiancé, Grace Crawford seeks sanctuary at the remote home of her sister, Catherine. It becomes clear that Catherine is suffering from paranoid schizophrenia, much like their late mother, who had taken her own life. While coming to terms with this heavy realization, Grace also uncovers another terrible little secret that has her struggling to maintain her own sanity and ultimately scurrying to save herself and her family from further harm.