Two friends work as cleaners whose jobs are to clean homes and places where people have died or dead bodies are found. One day, they are tasked with cleaning a house where there were three dead bodies inside. Their job is to clean the corpses that have rotted. When they arrived there, they found that there are strange things happening and then they discover a strange book.
兰斯林（丹尼斯·奎德 Dennis Quaid 饰）警官同时也是一个单身父亲，因公务繁忙，他无暇照顾两个儿子，大儿子亚历克斯无形中时常扮演父亲的角色。最近兰斯林被一桩连续杀人案缠住，每个凶案现场都发现了至少四名嫌疑人的踪迹，并且统一留下了“过来看”的血色留言，死者死于悬挂的状态充满了宗教意味，兰斯林从人体悬挂的铁架入手，发现这一干罪犯以杀人作为宗教仪式，并且以启示录中记载的“天启四骑士”自居。第一个受害者的华裔养女克里斯汀（章子怡 饰）主动找到兰斯林，坦承了自己与连续杀人案的关系，但是这不能阻止更多人受害，兰斯林惊见自己最不愿意看到的事情发生了……