|The Super Duper Sumos-Booma, Kimo, and Mooma-are back to stop Ms. Mister and her Bad Inc. monsters from destroying Generic City. Cousin Prima lends a helping hand and offers timely suggestions. Just don't call her "kiddo," and watch out when she operates construction machinery!
And times are tough. Construction crews attempt to tear down the sumos' apartment and build a new headquarters for Bad Inc. Pleasure cruise ships disappear around the world, and the sumos and Prima resort to a bathysphere dive, snorkeling, and more to unravel the mystery. A glass figurine sculpted in the image of Prima leads the sumos to Dr. Stinger's laboratory and inadvertently inspires the mad scientist to create a monster. A relaxing camping trip proves too close to nature when toxic waste from a Bad Inc. plant changes peaceable creatures into monsters. Then a killer dust ball throws lint into the sumos' search for their stolen yaks. What's a sumo to do?