Doctor Varmint and his beautiful assistant, Rosie Rodent, have made--and captured--a stunning scientific discovery: the mighty Kat Kong. But when he breaks free from his shackles and tears through the streets of Mousopolis, there's no stopping his terrifying rampage. Is anyone clever enough to halt this massive meowing menace?

When a new bunch of baddies arrive in town, Dog Man and his friends are called into action, but in order to save the day they need to join forces with Petey, the world's most evil cat.