Each card represents a Powerpuff girl and has a value on it. From your cards you play a specific girls card in an attempt to steal the girl from another player. They can then play cards to stop you. Once you do obtain a girl you can then play cards from any girl you own to defeat a villain (of the 3 showing) for points. You can not attack a villain with girls you controlled at the start of your turn unless you obtain a girl during your turn. This forces you to deplete your hand before going after points.
This is my retheme of PPG into a DC Comics Justice League utilizing Batman, Superman and Wonder Woman with appearances by Martian Manhunter, Flash, Green Lantern and Aquaman fighting many of their greatest villains.