Lucky Luke is escorting the Daltons during a prison transfer, when quite inadvertently, Joe saves the life of Hungry Hamster, son of Beastly Beaver. According to Indian custom, Joe becomes Hungry Hamster’s blood brother and as a consequence, is untouchable. Ditto for his brothers. The Daltons remain in the Indian Village and take advantage of their new immunity status. While they’re at it, they decide to get rid of Luke...until the day when Lucky saves Hungry Hamster’s life himself, becomes his blood brother and also...an untouchable. But the ties run deeper than blood and Luke is now also...the Daltons’ blood brother!!