Ten-year-old Sébastien (Fabien Chombart) is informed his mother is stuck in New York and will not be able to come for him for the school break. He is not enthusiastic about the idea of spending his free days in the school and decides to visit his grandfather Sébastien (Guy Bedos).
They are not acquainted and soon find themselves having to share their time with one another. His violinist grandfather did not know he even had a grandson and does not waste any time letting the grandmother of the child, Louise (Marie Laforêt), know about it. Louise, like Sébastien, was also unaware of it, although she made plain her willingness to help in any way she can. This news brings peace of mind, if only momentarily, to the musician, because, you see, his life was already in a state of mild chaos. His girlfriend is ready to leave him, his being fired from the orchestra and having to play in a nightclub to make his living make the coming of young Sébastien a new problem that has to be solved quickly.
Directed by Michel Drach, Il est génial papy! Offers light entertainment and some funny moments here and there, mostly the product of young Sébastien and the unexpected behavior in some situations. For instance, when he is not asking his babysitter Violette (Valérie Rojan) to show him her assets, his proclivity to hustle renders many situations humorous. He is definitively creative in that department!
