La vallée des bannis, written by Tome and drawn by Janry, is the forty first volume in the Spirou et Fantasio series, and the ninth from the Tome & Janry team.

In La vallée des bannis, carried away by a furious torrent during their passage through Touboutt-Chan (from the previous story La frousse aux trousses), Spirou and Fantasio regain consciousness in the hostile environment of the "Valley of Banishment", their destination.

Fantasio is soon infected by a mosquito carrying a virus, making him act extremely crazy.

He runs off into the wild, and Spirou is forced to begin exploration of the area with only Spip as a companion.

Spirou discovers the tragic destiny of the first people exiled in the valley, and while searching for other survivors and a way leading out of the valley, seeks a way to secure Fantasio's return and cure his state of madness.