陳先生(黃子華 飾)本來是最頂尖的特工，但因夥伴一次無心之失慘被停職，同時還得罪了女警余香(余詩曼 飾)，欠下情債。二十年後，城中名人相繼失常。陳先生再被委以重任，以為可大展身手，誰知此案與宅男圈內的藥物有關。為了社會安寧，陳先生只好化身不修邊幅的宅男查案，引發各種難題和笑彈。
Mr. Chan was the top agent. Unfortunately he has been removed from duties right after a mission failure, his partner (Wonder Child) made a mistake and offended the policewoman Ms Shek unintentionally. 20 years after, Ms Shek has no choice but put the problems aside to ask Mr. Chan giving her a hands for solving a mysterious case. With the evidence to show this case has been involved with a Cyber Goddess. Mr. Chan is inevitably to make up himself in a sloppy appearance, the situation become out of control.