Dibble's Double is the thirtieth and final episode of Top Cat.
Officer Dibble catches the gang betting on turtle races. Just then the Sergeant drives by and tells him to report for guard duty at the art gallery. Hearing that many tourists are coming to see a new exhibit, Top Cat prepares to rent parking spaces to them.
The Sarge tells Dibble to keep an eye out because Al the actor, master of disguise, is in town, and may try to steal some paintings. The thief uses several disguises to case the joint, but remains undetected.
When patrons start parking on the street, the parking business dwindles, so T.C. asks Dibble to enforce the parking ordinance, but he doesn't leave his post. T.C. hears a critic talking about abstract paintings and learns that some sell for thousands of dollars. He returns to Hoagy's Alley, attaches paint brushes to the turtles' tails and has them paint on a bed sheet. He hangs it up in the gallery, and a rich lady offers to buy it for twenty thousand dollars after the exhibition.
Al the actor disguises himself as Dibble and infiltrates the gallery. He knocks Dibble unconscious and takes his uniform then steals a stack of paintings, including Top Cat's. The other cats see him leave. When the Sergeant arrives, they tell him they saw Officer Dibble steal the paintings, so he chases after him. Al evades him by hiding on a rooftop.
Dibble wakes up without his uniform, hears about the theft, and realizes he's been framed. He escapes down the side of the building, and tells T.C. his situation. T.C. wants to turn him in until he says he can help retrieve the twenty-thousand-dollar painting. As they debate where to look, Al happens into the alley. After some chasing and much confusion, T.C. tricks the impostor into revealing himself. He also reveals that he was disguised as the rich lady, so T.C. won't be selling his painting for twenty thousand dollars.
- Dibble and his double recreate the Marx Brothers' famous mirror scenes.