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 Guardien (game master) both, while the last part is for the Guardien only.
From the back of the book (submitter's translationown from French):
"Clefs en Mains" is an RPG accessible for beginners. It puts you in the role of the Guardien, you can create characters from Terra Amata and play their adventures in various epochs from the univers of "Donjon".
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!