Nantes, 1839. Jules Verne is an intelligent, mischievous, daring and imaginative 11 year old kid. He demonstrates a boundless curiosity and wants to know everything. He loves making his own scientific experiments, causing havoc on more than one occasion.
When a hot air balloon is announced in the city, The XXI Century Adventurers, that is, Jules and their friends, Caroline, Marie and Huan- can not resist the tempation of examining it in secret.
At the same time, sinister forces opposed to progress conspire so that the presentation of this wonderful device ends badly.
Both groups get their way, giving thus the green light to risky adventures for the club members: abandoned in a hostile land, they must use their intelligence, their skill and, above all, their value to survive and unbreakable friendship.