Safely back in 1803 England, Merlin's Irregulars are more confident, proud, and powerful, but class distinctions complicate their relationships until the mages are called upon to rescue a vitally important French scientist and his family from Nazi-occupied France.

An abridged version of the tale of Sara Crewe, a pupil at Miss Minchin's London school, who is left in poverty when her father dies but is later rescued by a mysterious benefactor.