Formerly dead Milton Fauster tries to save his older sister Marlo from "eternal darnation" when she is sent to another educational level of the Underworld reform school known as Heck.

When goth teen Marlo wakes up in Fibble, the part of Heck that is reserved for liars, she is disgusted to find that she is in her younger brother Milton's body.

Dale E. Basye sends Milton and Marlo to Precocia, the circle reserved for kids who grow up too fast, for their latest hilarious escapade in Heck.
When Bea "Elsa" Bubb, the Principal of Darkness, tells Milton and Marlo Fauster they've gotten too big for their britches, she sends them to Precocia, the circle of Heck for smartypants kids who grow up too fast. There, the children learn adult jobs. William the Kid teaches bill collection. Mozart teaches...

After Marlo loses the War of the Words against her brother, she is whisked away to the deepest bowels of the underworld. Guilt-ridden, Milton agrees to work for Principal Bubb in hopes that he can locate his sister and somehow free her. But his nefarious mission-to "character assassinate" the reigning vice principal of Sadia: Where the Really Mean Kids Go-runs afoul when he learns the true identity of this mysterious individual. Meanwhile, Marlo wakes...