But Moomintroll and Snufkin recover it at night and hide it in the cave by the sea, where the Muskrat is spooked when his dentures transform into something mysterious and terrifying.

The Moomin Family travel to the Island of the Hattifatteners on a boat they have found, and the Moominhouse is transformed into a jungle when Moominmamma absent-mindedly drops a ball of poisonous pink perennials into the hat.

At night the jungle withers, and it is used as firewood to cook the huge Mameluke that the children previously caught while fishing.

The Moomins hold a party to celebrate the finding of Moominmamma's handbag, during which the Hobgoblin arrives (with a new hat) demanding the King's Ruby, but is refused by Thingumy and Bob.

A Finnish theatrical version of the book, presented in 1996–1997, has also been made in collaboration with the Friends of Moomins Association (Muumien ystävät -yhdistys) and the Tampere Theater.