The Northern cavalry doesn't look great: Colonel Stark's horse has emphysema, and Chesterfield's horse is parkinson's... It's impossible to properly load the enemy. Once again, the future of the unionists is in the hands of Blutch and Chesterfield. They are now designated volunteers to go, disguised as settlers, to pick up from the Comanche tribes of Texas the horses necessary for the continuation of the war. The opportunity to find on the road old acquaintances, like Plume d'argent, or Colonel Appeltown and his daughter Amélie. But also to make much more unexpected encounters, especially for Blutch who will discover himself... a twin brother among the Comanches!