Sam, Philippa, Thomas, and Max have just started to recover from their capture and subsequent escape from Rattigan. But the children's lives don't stay quiet for long.A slew of bank robberies is terrorizing the city. And when Professor Farnum, the ringmaster of the museum's now immensely popular flea circus, is charged with murder, the search for the real killer uncovers a plot much bigger than any individual crime-a plot that can only be the work of Nicholas Rattigan.