In Comanche territory, a group of soldiers is escorting a hunting expedition organized by the wealthy Mister Rockson. He has also brought along his nephews, Jason and Evelyn, both just over adolescence. When two young Comanches attempt to steal some of the soldiers’ horses and are killed, the men led by the warlike Standing Bear massacre the expedition in retaliation and abduct Jason and his sister.
Major Wolf, commander of Fort Fulton, calls in the Spirit of the Hatchet for help, and the search for the missing youths begins.
Zagor and Chico reach the Comanche village, where they meet the chief Crow Flight, a reasonable man who would even be willing to release the youngsters. However, the war chief Standing Bear disagrees and challenges Zagor to a duel. Zagor emerges victorious, but when he goes to the hut where the two youths were being held, he discovers that someone has already taken them away. It is the Indian Seven Clouds, whose intentions are far from clear…
Meanwhile, a column of soldiers that includes the boys’ father, Senator Rockson, approaches the encampment. To avoid a clash, Zagor convinces Crow Flight to move the tribe away and goes to parley with the soldiers. With little success, since the senator has the abandoned village set on fire.
At this point, Zagor sets out on the trail of the three fugitives, persuading the senator to wait three days before launching further reprisals. Unbeknownst to him, Standing Bear eager to take revenge on Zagor and reclaim the two white youths and Pawnee Charlie, an army scout assigned by Rockson, are also following the same trail.
Meanwhile, Seven Clouds, though with a certain harshness, gradually teaches the two youngsters how to survive in the wilderness.
Standing Bear, attempting to kill Zagor by dropping a boulder on him, instead wounds Chico, who returns to the military camp in an effort to buy more time. Zagor then survives a charge by prairie bison, but Pawnee Charlie, observing from afar, believes him trampled to death beneath their hooves. Seven Clouds and the two youths reach an Indian burial ground, where he finally declares his intention: to fight Zagor before the bodies of his ancestors. He then stuns Jason and Evelyn and ties them to the funeral scaffolds. Meanwhile, Standing Bear lies in wait nearby, armed with a rifle.
Zagor finally arrives and is confronted by Seven Clouds. In the duel that follows, Seven Clouds has the chance to deliver a mortal blow but holds back; Zagor takes advantage of this hesitation and knocks him unconscious. At this point the treacherous Standing Bear intervenes, grazing the Spirit of the Hatchet with a rifle shot. Before he can finish him off, however, young Jason manages to pierce the Indian with an arrow.
Seven Clouds declares that his sole intention was to measure his fighting skill against Zagor and releases his prisoners.
Meanwhile, Rockson, convinced by Pawnee Charlie that Zagor died in the bison charge, intends to attack the Comanches, risking the massacre of his patrol. But just before the clash, Zagor reappears and returns the children safe and sound to the senator, thus preventing a bloodbath.
