Two kids are running across a field, playing. The girl, Julia, falls but the boy Andy helps her. As he tends her wound he promises always to be there for her. The two are joined by another girl Sandy. But these kids aren't just playing, they're training! To be secret agents, and they are on their way to the US for further training.Years later. We meet the troubled director James (Patrick Tam) as he's getting ready to shoot his next commercial. His two ADs (Assistant Directors), worry about him because he hasn't had a girlfriend in a long time, and they fear for his sanity. The actress for the commercial is late, but while they wait for her James spots the perfect woman walking down the street (yes, you've guessed it! It's Shu Qi!). He quickly turns on the camera and manages to shoot s few seconds of footage with her, before she drives away in a car. Soon we learn that the woman is in fact Julia. She's in town on a secret mission. Andy is with her and shows her the apartment where she and her new partner Candy are going to live. But Julia wants out of the business, and begs Andy to go to their boss Mr. K and release her from her obligations. In Flashbacks we see how Sandy, was killed on a mission and with her dying breath begs Julia to get out before she gets hurt too. Later Candy arrives. Much to Julia's surprise she looks and acts more like a giddy schoolgirl than a secret agent and confesses that she joined the business "because of the excitement"! In the meantime James' ADs have tracked down Julia's apartment. James show up at her place and tries to woo her (and offer her a part in a commercial). She yells at him, and knocks him out, however, this only makes him more determined. With the help of his trusty ADs, he rents an apartment across from the girls, so that they can observe them and find out who Julia really is. Meanwhile the two girls gear up for their big job which involves stealing something from a large company American Investment Corp. (AIC) which in reality is a front for another organization (switch the letters around and you'll get the idea). They go to work in AIC as cleaning ladies, while the boys move to their new apartment and set up surveillance equipment. Naturally the last thing two female agents need is a bunch of horny boys keeping track of their every move. Needless to say this is a recipe for disaster.