When the hamsters in Ms. Weintraub's room start acting a little strange, everyone thinks the problem must be the alien vitamins that Pleskit has been feeding them. But even after Pleskit stops the vitamin treatments, the hamsters continue to get bigger—and stronger—and crankier. Clearly, something else is at work. But what? To answer that question, Tim and Pleskit will have to solve a mystery, track down an enemy, and defend themselves against a trio of the most dangerous hamsters the world has ever seen!