S1·E51 The Gang's All Here

When the local policeman warns Heathcliff that any more of his pranks will land him in jail for life, our little monster decides he'd better reform. And when a new cat gang moves into town to terrorize the neighborhood, Heathcliff is forced to stand passively by and let them take over his territory. But it isn't long before the policeman is back knocking on Heathcliff's door; only this time he's come to ask Heathcliff's help. Heathcliff can do anything he wants, just as long as he runs those nasty new cats out of Westfinster! Things return to normal in no time as Heathcliff shows the punks who's really the boss!