AllMovie

The title character in this Oscar-nominated cartoon is a tough, derby-hatted mouse named Muscles. After beating up all the cats in Hogan's Alley, Muscles receives an urgent message from cousin Jerry, who tells him of the "serious trouble" he's having with his feline nemesis Tom. Wasting no time giving Tom a going over, the Bogart-voiced Muscles warns the cat to lay off Jerry. Rather than heed this warning, Tom takes a crash course in bodybuilding--but still Muscles is able to clean his clock. In desperation, Tom calls in reinforcements, namely a trio of nasty-looking cats from Dirty Work Incorporated. But Jerry's cousin isn't called "Muscles" for nothing...and that's not the half of it!