Nathan is just getting started with his training for secret organization BUM when greasy green globs of goop start oozing from every faucet in town. Gross! When BUM asks Nathan to investigate, he and his friends Abigail and Mookie follow the trail to the smelliest place they can imagine—deep in the heart of the sewers of East Craven. And what they encounter there may end Nathan's career as a zombie spy before it has even begun….