There Innes and Perry have established an Empire of Pellucidar, actually a confederation of tribes, and attempted with mixed success to modernize the stone-age natives.

Perry transmits a lengthy account of how this has come about, as reported by Innes's native comrade in arms Tanar, and appeals for aid from the outer world.

The empire's forces succeed in repulsing the Korsars, but the raiders retain as hostage Tanar, son of Innes’ ally Ghak of Sari.

Leaving his forces to construct ships to counter the enemy fleet, Innes and his comrade Ja of Anoroc set out alone to rescue Tanar, guided by their own prisoner, the Korsar Fitt.

Eventually the derelict ship drifts to Amiocap itself, but the island's suspicious inhabitants take the two for Korsar spies and imprison them in the village of Lar.

But Bohar's group of Korsars attacks Peraht and kidnaps Stellara, while Tanar falls prey to the Coripies, a cannibalistic subterranean race.

After confirming the existence of the polar opening they turn south again, bound for Sari, only to encounter a large party of pursuing Korsars, at which they split up in an attempt to ensure some at least can carry word back to the empire.