When Ozzy discovers there are lice eggs in Hector's hair, he and Drix venture onto the scalp to knock the eggs off, only to end up running into the monstrous Mother Louse!

Ozzy thinks he's going to have a baby, but it turns out he's been infected with an intracellular bacteria by returning villain Strepfinger. Ozzy and Drix must find a way to destroy the parasite growing within Ozzy before it spreads its infection to all of Hector.

Hector binges on candy, creating a sugar rush that speeds up all the cells and causes the bacteria population to swell. When his parents cut him off sugar, his drop in blood sugar slows all the cells to a crawl. But the bacteria need sugar, so they form an army to raid Hector's sugar reserves. Now Ozzy and Drix, with the help of the Mole, must take on the bacterial army.