After Numbuh 1 defeats Knightbrace, Numbuh 4 finds the Toilenator trying to flood the Treehouse with sewage (as he has tried to do at the beginning of the game). Numbuh 4 makes his way through the flooding treehouse, defeating the Toilenator's new henchmen, Scrummy Mummies and Poohemoths, to his room. Numbuh 4 challenges the Toilenator to a race to Numbuh 4's toilet. When Numbuh 4 wins, the Toilenator is sent to the C.O.O.L.B.U.S with the other villains.