FERGUS CRANE! YOU ARE IN GREAT DANGER! I AM SENDING HELP. Signed T. C., your long-lost Uncle Theo
At midnight, a winged box flies in the window with a warning for nine year old Fergus. Then a winged metal horse whisks him off to meet his long-lost uncle and penguin helpers, Finn, Bill, and Jackson. Captain Claw may teach tunnelling for free to the five smallest applicants aboard school ship, but the pirates plan a six-week trip to Fire Isle, where the volcanic eruption nine years ago has cooled enough to gather valuable fire diamonds from the caverns, and where his father, Captain Marcus Crane vanished.