女干探DODO性格泼辣火爆，为破案会不惜用尽手段，令上司及黑道中人都同样头痛。某日，警方高层指派DODO与廉署行动组组员MAY合作办案。MAY及出身富裕家庭、斯文大方、做事讲究规章程序之人，两人碰面，已看对方不顺眼。DODO与MAY奉命追寻数年前在黑社会仇杀中被害的潮州龙头阿B出面作证人，顶证现在纵横黑白两道的富商陈东，由于彼此怀有邀功私心，调查一开始，两人便面和心不和用假料假线陷害对方，其后DODO找到帮会小喽罗破毛，逼迫其讲出阿B的藏身地，私身扮成修女，进入一新界潮州福音团契组织侦查。另一方面，MAY亦查得一名问题少女将带同阿B失敌之幼女返港与B重聚，亦扮成串女进入团契调查。DODO与MAY在福音契中为掩饰身份，要做一些与性格完全相反的行为，苦不堪言，笑料百出，经过试探，认定身为改邪归正之牧师阿B最为可疑，遂各自出本领接近阿B。

女幹探DODO性格潑辣火爆，為破案會不惜用盡手段，令上司及黑道中人都同樣頭痛。某日，警方高層指派DODO與廉署行動組組員MAY合作辦案。MAY及出身富裕家庭、斯文大方、做事講究規章程序之人，兩人碰面，已看對方不順眼。

Dee (Carol Cheng) is a disheveled, hot-headed HK cop; Apple Yu (May Lo) is an urbane, designer-dressed inspector from the ICAC. Now, they're partners trying to bring down (still another) triad crime ring. To intimidate Apple, Dee dresses like a model, but finds that her partner has taken on a street-punk guise to intimidate her. They locate a priest who's a triad defector; and while Dee takes a nun's guise, her partner tries to pull off being a junkie in withdrawal.