Speedy Gonzales is terrorizing the residents at a Mexican rest home for neurotic cats. Dr. Ben Crazy, a spoof of Dr. Ben Casey, calls Daffy Duck to rent a rodent trap. Daffy brings over Herman the robot and tells the doctor to insert twenty-five cents, but Herman bites him when he inserts a slug instead. Daffy takes Herman down the hall to look for Speedy. Herman easily catches the mouse, but when Daffy thinks out loud about all the money he'll make without having to share it, Herman lets him go. Daffy agrees to split the money with Herman and they track Speedy to a telephone pole outside. Daffy chases him across the wires until he gets zapped. Then he dresses as a female mouse to lure Speedy out of hiding. However Speedy points Herman's rodent radar at Daffy so the robot attacks him. When Speedy invites in his cousin Ramon, the biggest rat in Tijuana, Herman revolts, and Daffy is thrown out the window.