The Space Brigade are relaxing after their spectacular triumph over Princess Petronella and her plans to destroy Earth when they receive an intriguing letter. The planet of Shobble wants to employ their services. Most of the population are virtually slaves, forced to mine for marshmallow and drill for chocolate (the ingredients of Shobble-Choc, the most divine chocolate in the galaxy). Led by a girl called Topaz, the workers are beginning to rebel and the commander-in-chief wants the Space Brigade to squash the rebellion. At first Nicola refuses to be involved but then something happens that leaves her with no choice. Now the Space Brigade are on an incredible journey, and along the way they'll learn new skills, make new friends - and they might just change this planet's history forever.