S.H.E's Ella Chen (New Perfect Two) joins hands with screen heartthrob Mike He (Love Keeps Going) in Bad Girls! Ella plays spunky high-school girl A-Dan, who, along with her best friends Pei Pei ("otaku's goddess" Da Yuan) and Xiao Mi (Beatrice Fang), forms the notoriously prone-to-violence trio known as the "Bad Girls". She takes it upon herself to deal out justice, protect other girls from bullies, and, most importantly, punish the insufferable boys. This summer, young popular idol Justin (Mike He) comes to A-Dan's school to shoot his latest romantic movie, and that makes the girls in town crazy. But it is the nonchalant A-Dan who, by pure chance of fate, accidentally crashes into the filming lot, and is assigned the female lead role opposite the arrogant Justin! There is a problem - she has no prior romantic experience at all..