A man called Paul is working after hours and is murdered by a supernatural entity in the shadow. When his son, the boy Martin, is frightened by the same creature, he sees his mother Sophie talking to an imaginary friend called Diana in the shadow of her room. Martin does not sleep anymore during the night but in classroom and his older stepsister Rebecca that lives alone is summoned by the social assistant. She brings Martin home and recalls he own experience with Diana years ago when she was young. Sophie and her boyfriend Bret investigate the connection of Sophie with Diana and come up to a scary revelation about their past.
《鬼关灯》描述一则不为人知、潜伏在黑暗中的骇人故事。丽贝卡(泰丽莎•帕尔默 饰)离家时，以为她已经抛开了童年的恐惧。她从小就不确定灯熄了之后，眼前的一切到底是不是真的。而今，她幼小的弟弟马汀也经历了相同无法解释的恐怖事件，过去曾威胁她、那个曾经让她以为自己疯了，甚至危急她生命安全的恐怖“东西”，再度出现了。这次，随着丽贝卡愈来愈靠近真相，一旦灯光再度熄灭，他们所有人的生命都将陷入危险。然而，她们也将逐渐察觉，一切的恐怖源头，与她们的母亲苏菲亚，似有关联。在母亲消失后，曾经有一个非常要好的朋友黛安娜，在她身上发生了非常不好的事情，事隔多年之后，黛安娜回来了，他们唯一要做的，就是只要把灯关好.. ….