Blunderplod, the small, fat, young cousin of Mr Littleplod, finds himself in a spot of bother. Whilst searching for treasure, he’s been captured by the nasty one-armed, one-legged, one-eyed pirate captain, Peg Leg Julian.
Peg Leg wants the treasure map for himself, of course, but because Blunderplod won’t tell him where it is, the captain is forcing Blunderpod to walk the plank from his submarine, where poor Blunderpod will be eaten alive by evil yellow crabs!
In a last-ditch effort to save his skin, Blunderplod exclaims that a human 9-year-old boy named Noah Ramsbottom has the treasure map. Peg Leg Julian has Blunderplod write a letter to Noah. When the boy wakes up, he finds a pigeon on the window ledge with a note on his leg. The letter is from Blunderplod and he begs Noah to help him.