This core book, the only item of the RPG so far, contains rules, settings, bestiary, a section for arms and equipment, magic and two pre-made adventures. The first part of the book is for players and the Guardian (game master) both, while the last part is for the Guardians only.
From the back of the book (submitter's own translation from French):
Clefs en Mains (Keys in Hand) is an RPG accessible for beginners. It puts you in the role of the Guardian, you can create characters from Terra Amata and play their adventures in various epochs from the universe of Donjon (a series of French graphic novels by Sfar and Trondheim, also available in English as Dungeon).
Will they participate in the political life of Antipolis during "Potron-Minet"? Work at "Donjon" in the epoch "Zénith"? Try to fight against the dark armies of the Géhenna during "Crépuscule"? Or even live totally different adventures?
It's your choice!