The Hero Gang is a nasty group of thugs terrorizing Hong Kong with their killer robots, Pioneers 1 and 2. While Pioneer 1 looks like an oridinary robot, Pioneer 2 has been modelled on Maria, the gang's #2 thug. When Pioneer 2 gets damaged during a mission to kill an outcast gang member, an inventor on the police force takes her and changes some of her programming. This new code, plus a few injuries to her logic center, start causing Pioneer 2 to develop her own personality.