Summer session is in full swing at elite Dartmoor Academy. With classes like opera appreciation, it's no wonder Domino, Loaf, Lucy, Sonny and Witz, an imaginative group of 7-year-olds, are yearning for a little excitement. On a field trip to an aquarium, the Stinkers-so named by their stuffy, overbearing principal, Mr. Brinway (B.D. Wong)-manage to sneak away in search of adventure and find it in Slappy, a 100-pound sea lion who seems none too thrilled with life at the theme park. But sneaking a sea lion onto the bus proves easier than finding a place to hide him. And when Boccoli (Sam McMurray), an infamous animal thief, arrives on the scene with plans to kidnap Slappy and sell him to a Bulgarian circus, the Stinkers must use all their wits to outsmart Boccoli, the principal and their parents.