Youri, 16, has lived all his life in Gagarine Cité, a vast red brick housing project on the outskirts of Paris. From the heights of his apartment, he dreams of becoming an astronaut. But when plans to demolish his community's home are leaked, Youri joins the resistance. With his friends Diana and Houssam, he embarks on a mission to save Gagarine, transforming the estate into his own 'starship' - before it disappears into space forever.