Iggy is different from the rest of his tribe, the Urks. He isn't interested in the usual things such as flint tools, hunting or boulder-rolling. He's always daubing on the walls of his cave or coming up with infuriating new ideas. According to his dad: 'We don't need new ideas - we have plenty of old ones.' Iggy's latest invention is a primitive scootalong or Stone Age skateboard. His parents don't want him playing outside in case the neighbours complain. Besides, they have more important things to talk about: tomorrow is the Sons of Urk ceremony, when boys who come of age are accepted into the tribe as hunters. Iggy is eager to take part, but he'll have to pass the ritual initiation test, which means facing the one thing he dreads more than anything: snakes!

Old Grumbly, a massive volcano that looms over the Urk valley, has begun to rumble and many Urks fear The End of the World is nigh. They agree that the only way to avoid catastrophe is for someone to climb the volcano and make an offering to the ancestors. Preferably, this someone should be the Urk selected to succeed Chief Hammerhead at the momentous Anointing Ceremony . . . which just so happens to be Iggy. Now Borg can implement his latest plan to snatch control of the Urk tribe for himself, with the help of the Noneck tribe we met in the first book in the series, Oi, Caveboy!. It's time for Iggy to come up with a cunning plan.

Iggy discovers a young member of the Henna tribe lost in the jungle (Henna, so-named for their fiery red hair and penchant for covering their faces in mud). The girl is wearing some rare and precious firestones, which mesmerise the Urks, especially Borg, who devises a new and devious plot to become Chief Urk. Iggy must embark on a dangerous journey to return the Henna girl safely to her tribe in the Cloud Mountains. But when he gets there, the welcome is not exactly what he had in mind.Time for a very cunning plan.

Old Grumbly, a massive volcano, has begun to rumble and many Urks fear the end of the world is nigh. They agree that the only way to avoid catastrophe is for someone to climb the volcano and make an offering to the ancestors.

Iggy is excited as he sets off with Dad on his first hunting trip. More so when they find a set of footprints too large even for a mammoth. Alongside are a heap of bones and a pool of slime the colour of egg white. Iggy wants to hunt the creature, but Dad is suddenly anxious to get back. Later, Iggy's Grumma tells him about the Slimosaur - a great scaly beast which coats you in slime before devouring you in one go. Many moons ago it terrorised the tribe and a dozen Urk children vanished. 'Nothing to worry about,' she says. The Urks have had a poor harvest and food is running very low. Chief Hammerhead calls the Elders to discuss solutions to the food shortage. It's decided that to appease the spirits one of their tribe must be sacrificed to the Slimosaur. They cast lots and to Iggy's dismay his friend Umily draws the shortest stick. Umily is taken to the forest and bound to a stone. She hears rustling noises. Something is coming . . . Iggy appears! He has come to the rescue! He is armed with a small catapult and a net. Hopefully he has a cunning plan.

Captain Underpants meets Marvel comics in this very funny and very silly new series from the bestselling author of Dirty Bertie