Mooney is an old classmate of Kat's who was sick of always being in her shadow. He has now joined up with Broodwing and is using his remote control robots to attack the city. Mooney's plans are foiled and he is brought in by Kat as the S.P.D. Kat Ranger.
Kat's capture of Professor Mooney is exclusive to S.P.D. only. In Dekaranger, his counterpart Hymal instead tried to commit suicide but Kat's counterpart Swan stopped him and then slapped him before he surrendered and allowed himself to be taken in more formally.