汤警官（胡枫 饰）陈警官（高雄 饰）是警察学校的教官，近日里，学校里频频发生科学无法解释的灵异事件，导致学员们不敢再来上课，无奈之下，两人找到了法师驱鬼，方才得知原来是因为陈警官的前世害死了一家四口人，四人化作厉鬼，今世来找陈警官报仇。化解这劫难的方法只有一个，那就是找九名生肖属龙的警员摆出九龙追魂阵。 陈警官隐瞒了驱鬼的事实，以一虚构的任务为名，成功召集了属龙的九人，其中有一个特别张狂的女人阿李（吴君如 饰）引起众人的反感。最终，学校里闹鬼的事情还是败露，当九人想要逃走时，却发现他们已经中了厉鬼的计，无法离开，九龙追魂阵是他们生还的唯一希望。

Police School is haunted. Chan Sir and Tong Sir in order to drive out the ghosts, so they find out nine police, who is the dragon-year born, to practice an array. Because of arrogant of Inspector Li Lan Yuk, makes others with bad feeling. They decide to play a trick on her and have lots of joke. They know the goal of training is to seize the ghosts, they all left the training. But the camp is already controlled by the ghosts, causes they stay here to help Chan to seize the ghosts. In Lunar night, on July 14, Chan unable to seize the ghosts, Madam Lee takes out the family secrets and turns into a Taoist priestess to fight with the ghosts. At last, Lee and master drive out all the ghosts