Alex, Antoine, Jeff and Manu. Four friends, four years later. Their relationships, friendship, shared secrets, feelings of guilt and their desire to change and improve.

When Huguette, a 78-year-old former school principal, ends up homeless because she did not pay her rent, her neighbor Marion offers her a deal: a roof in exchange of her help to prevent the teenager she is raising alone, Rémi, from failing school.

The grandfather welcomes us into his blue grotto, there was still beautiful memories of childhood to tell Kirikou: the times when he helped the men and women of his village and elsewhere ... He tells us how Kirikou, thanks to his bravery and intelligence, came to the aid of the strong woman. He tells us by what trick the little hero found the grumpy old man, who had been lost in the bush, and how a cherry threatened by the witch was finally able to pass on his knowledge to the villagers. We also discover the secret of a mysterious blue monster, and finally through a flute linked to the family of our small and valiant heroes, the magical power of music.