After fifteen years of war, Pellucidar's slavemasters, the dread Mahars, had been conquered. But the young Pellucidarian Empire, ruled by David Innes, was unprepared to face a new menace, the deadly Korsar pirates. Bravely the Empire's primitive warriors fought, but many were lost - and Tanar of Sari, one of Innes's most courageous warriors, was captured.

All through the terrors of the hideous realm of the Buried People of Amiocap and the unspeakable horrors of the Korsar's dungeons, Tanar refused to break. He was determined to escape, for he had dreadful news for the Empire - the Korsars had captured David Innes!