Van Dergard visits places along the border looking for new people to fight in his gladiatorial shows. One of the fighters is Shamrock, who wears a powerful Indian amulet. Brave Wolf, from whose tribe it was stolen, is trying to recover the amulet.
The Hidatsa tribe chooses a new chief between two rivals. According to an old tribal custom, rivals compete in a game with seven arrows, but one of them is wounded, so Zagor takes his place.