Owen wakes up in the Montana Territory tied to a wooden pole in the middle of a Blackfoot Indian village. He doesn’t remember his name, where he came from, or anything about his past. The Blackfoot Indians believe a book that was lying beside Owen when he was captured has spiritual powers and helped him survive an attack when all the others in his large wagon train were killed.

When Owen is restored to health, a Blackfoot chief named Askuwheteau forces him to play a game called the chase game to see if the book he carried with him has spiritual powers. If Owen survives this game, which no captive or warrior has before, it will prove the book they call Big Medicine has spiritual powers and his life will be spared. If he loses the game he will die and they will destroy the book. Can Owen outlast the twelve-armed Blackfoot warriors chosen to chase him with just the arrow he pulled out of the ground to start the chase game?

At the same time, a white woman held captive by Chief Askuwheteau since her childhood had prayed to God every day to send someone to rescue her and take her back to her own people. Just when she thought her prayers had been answered, a Blackfoot warrior named Megedagik traded ten Appaloosas for her and took her away to be his squaw. Had God forgotten her or had he always planned on her living among the Blackfoot Indians?

In another part of the Montana Territory, hostile Indians besiege Fort Pennington. Supplies and ammunition are running low while the defenders inside the fort fight two Indian tribes for their lives. Can a dispatch rider named Corporal Kessler, a scruffy old mountain man named Hobbs, and a book the Blackfoot call Big Medicine save the lives of the soldiers and settlers defending Fort Pennington, or will they all be killed by the hostile Indians besieging the fort?