Sixth-grader Alley Katz is innocently trying to help a bunch of kindergarteners when the burrito hits the fan. Literally. A burrito. A ceiling fan. A hail of beans. Now he has to get an A on his science test or he'll be transferred to the dreaded Steggles Academy.

An A seems impossible! Alley is kind, intrepid, and well-liked, but for some reason he doesn't get graded on any of that. So the principal assigns a peer mentor to help: Rex, a fourth-grade genius who wears a bunny suit.

Alley is totally in favor of both bunnies and fourth graders, but he doesn't need Rex. He has his own foolproof plan to ace the test. Still, Rex is determined to fulfill his duty as Alley's mentor--and he may need some help of his own. One boy needs to stay in school, the other needs to get through it. Can this odd couple save the day--and each other?