啄木鸟（曾志伟 饰）和甘油条（陈友 饰）是同事兼好友，两人相识多年，默契十足，感情十分要好。某日，在执行追捕黑帮大佬阿成（沈微 饰）的过程中，两人结识了警花吉吉（古嘉露 饰），三人结成搭档。于是，在啄木鸟和甘油条之间，一场异常激烈的撩妹比赛拉开了序幕。虽然啄木鸟能说会道十分神气，但甘油条似乎更加喜欢内向腼腆的甘油条。

Once there are two detectives in the police force, Fatty and Lanky, they have been very, very good friends, that until the day Gigi comes to their department for work. Fatty and Lanky immediately go after her skirt. Fatty and Lanky must find Boss Sin. They try to get information from Sin's man Fairyman who considers himself the biggest lover in town.