After the Marsupilami causes a series of disasters, Spirou and Fantasio finally resolve to bring the strange animal back to its birth place, Palombia. Unfortunately, it’s a nation in turmoil they find upon their arrival. The military is all-powerful, rumours of impending war are growing and a ruthless tyrant has seized power. To counter the dictator’s plans, the two adventurers’ only weapon is the Count of Champignac’s latest outrageous invention: a mushroom extract that makes metals go soft...

Spirou and Fantasio are spending a few days at Champignac Castle, keeping an eye on the estate while the Count is away visiting family. One night, as they are preparing to watch a comet pass in the sky, Fantasio’s clumsiness causes them to lose consciousness. They awaken to the very noisy arrival of de Champignac aboard one of his strange machines – except that the old man claims to be not the Count himself, but one of his descendants ... back from the future!

Spirou and Fantasio are famous – among other things, as the official discoverers of that legendary creature, the Marsupilami, one of which often accompanies them on their adventures. So when one of their conferences is cancelled in favour of a documentary film from an unknown author, they are understandably irritated... until, that is, they realise the film is the very first to record the family life of wild Marsupilamis!

While on an expedition in Antarctica, the Count of Champignac makes an extraordinary discovery: a still-viable dinosaur egg! Having brought the precious find back to his castle, he invites a few colleagues over – along with Spirou and Fantasio – and sets about hatching the egg. But working towards scientific progress isn’t easy when one is somewhat absent-minded ... and saddled with a whimsical Marsupilami ‘assistant’! Soon, life in the village of Champignac becomes rather complicated ...

Accompanied everywhere by his friend Fantasio and his pet squirrel Spip, Spirou is an adventurous reporteer who fights all manner of villains in every corner of the world.

Fantasio, chasing a scoop, slips through a cordon sanitaire surrounding a cargo ship fresh from Antarctica. He’s hoping to investigate some disturbing rumours about the base where the ship comes from. But a seriously ill man has escaped the quarantine and begs for assistance. The Count of Champignac can help, but only if he has access to a very rare toxin – one that is stored, for example, in that mysterious ice base, where more patients await...

Spirou and Fantasio’s friend, the Count of Champignac, asks them to join him in Australia, where he has heard that an ancient monolith is still standing. When they arrive, Champignac’s colleague Walker Donahue informs them that Champignac has been abducted by local gangster Sam. The monolith they’re after stands in the vicinity of an aboriginal mining village, which is constantly prey to white prospectors trying to steal indigenous resources. Spirou and Fantasio must save Champignac from Sam’s clutches and help him find the legendary monolith while standing by the aboriginal people.