Dewey snitched on his brothers. He must be tortured. So Malcolm and Reese snag a scary-looking stuffed monkey and make up creepy stories to terrify the little tattletale. It turns out his monkey has a name - Banana Joe, and that to all those who don't show him respect, bad luck will come. Who'd believe that monkey malarkey? Not Malcolm, he's too smart. Not Reese, he's too tough. But when bad things start happening, it looks like neither brains nor brawn are any match for a malevolent monkey who's been mocked!