Nurse Liang Shanbo and Actress Zhu Yingtai are mismatched cousins who just inherited a rental home from their late relative. When they moved in, they discover that a room has been rented out to a man named Ben, who turns out to be a criminal gangster. One night, when Ben returns home, bloodied and injured, he collapses into Yingtai's arms and whispers a code in her ear before he dies. Not knowing what the code leads to, Yingtai and Shanbo are later visited by a man claiming to be Ben's brother who wants to solve the case. In the meantime, gangsters believed to be involved with Ben's murder want to retrieve the code from the girls, whom they think were told by Ben what it actually unlocks.

할머니께 물려받은 아파트에 함께 사는 두 사촌. 티격태격하느라 정신없이 지내던 어느 날, 아파트 세입자가 눈앞에서 죽어버리는데. 이후 경찰이고 조폭이고 할 것 없이 찾아오는 자들이 많아지고. 대체 어떤 일에 휘말린 거야, 우리?

　　梁山伯（郑裕玲 饰）与祝英台（张曼玉 饰）是情同手足的表姐妹，彼此之间感情十分要好，两人靠着收租维生。阿本（潘震伟 饰）是两人家中的租客，某一日，他突然离奇死亡，梁山伯和男友装帅（陈百祥 饰）对阿本的死因产生了怀疑。一位名叫山姆（林俊贤 饰）出现自称是阿本的弟弟，领走了阿本的遗物。 　　杀手大蟒蛇（韩义生 饰）绑架了梁山伯和祝英台，命令他们交出阿本的遗物，好在山姆和装帅及时赶到，两位柔弱女子才幸免于难。徐警督（关明玉 饰）找到了梁山伯等人，让他们交出神秘玉佩，原来，徐警督正是杀害阿本的真凶，而山姆的真实身份则是调查整个事件的警探。