为了复习备考，阿力（方力申 饰）和朋友搬进了地处偏远的999号单位，然而，入住没多久，阿力便发现身边似乎开始发生一切科学无法解释的灵异事件。空洞走廊里的嬉闹声、浑身是血的男人、若隐若现的脚步，这些只有阿力注意到的诡异之处，究竟是现实还是幻想？

Eric (Alex Fong Lik-Sun) and Cheun (Sammy) are two medical students who opt to rent a flat in a secluded housing estate, the reason being to concentrate on their upcoming exams. Their best intentions go south damn quick; first of all, Cheun wastes time and acts extremely annoying, thereby ruining any chance at serious study time. Second, there may be vampires in the building. Eric becomes slightly enamored of Jade (Miki Lee), a pretty young thing who lives in the building with her older sisters (Zuki Lee and Cynthia Ho). But after a series of weird noises and the appearance of a man bleeding from the neck, Eric thinks something may be up. He enlists the help of TV occult expert Mister M (Yuen Wah), who all but confirms Eric's suspicions: the sisters are vampires. Worse, they must suck the life out of one good man to cure their aversion to daylight, and have ear-marked Eric as the designated \"good man\".