Christian, a visionary scientist, studies wild geese. For his son, a teenager obsessed with video games, the idea of spending a holiday with his father in the wilderness is a nightmare. However, father and son will get together around a crazy project: save a species endangered, thanks to the ultralight of Christian! Then begins an incredible and perilous journey ...

Paris 1930. Paul has only ever had one and the same horizon: the high walls of the orphanage, an austere building in the Parisian working class suburbs. Entrusted to a joyful country woman, Célestine, and her husband, Borel, the rather stiff gamekeeper of a vast estate in Sologne, the city child, recalcitrant and stubborn, arrives in a mysterious and disturbing world, that of a soverign and wild region. The huge forest, misty ponds, heaths, and fields all belong to the Count de la Fresnaye, an elderly taciturn man who lives alone in his manor.