Chronologically, this is the fourteenth and final Allan Quatermain novel published, although the events of the novel Allan Quatermain occur after it. It also the final Allan Quatermain novel in the trilogy involving the taduki drug and Lady Luna Ragnall, following The Ivory Child, and The Ancient Allan. Allan Quatermain, feeling awkward toward Lady Luna Ragnall after their recent taduki-induced vision in The Ancient Allan, in which they were nearly married, refuses three invitations from Lady Ragnall to return for another vision and has vowed never to use the drug again. Lady Ragnall herself informs Allan that she has used the taduki once more and discovered that their ancient counterparts, Amada and Shabaka, were indeed married. Allan reads in the newspaper that Lady Ragnall has traveled to Egypt for the winter. Six weeks or so later, Allan has a psychic experience and later learns that Lady Ragnall had died of heart failure at that moment at the site of her husband's grave in the Temple of Isis. Allan inherits her estate, coveted by Lord Ragnall's next-of-kin, Mr. Atterby-Smith. He distributes it to charities except for a box containing the taduki drug which Lady Ragnall had left him. He is tempted to break his vow and use it, but finally resolves not to when his friend, Captain John Good, calls on him. Good is able to persuade Allan to use the drug and the two enter into their vision. Allan awakens as Wi, an civilized man living in the barbaric ice age. He belongs to a culture that reveres a man and mammoth frozen in ice as their gods. Wi challenges and kills his chief Henga and institutes reforms in the tribe: monogamy, decision by council, the use of new technology, etc. His friend Pag, an outcast, rises in power in the tribe and is able to stop a pack of wolves from attacking. Wi and Pag travel into the wilderness to fight off a saber-toothed tiger and discover a beautiful young woman, unconscious, in a canoe. Wi falls in love with Laleela, as does Wi's friend Moananga. Most of the tribe regards her as a witch and Wi's wife Aaka wishes for her to be killed. Pag convinces Wi that he must marry Laleela in order to protect her, but Wi realizes this will break the oath of monogamy he has imposed upon the tribe. A tribe of red-bearded warriors attacks; Wi also battles the aurochs. When he rejects the ice-gods the tribe demands someone from his house be sacrificed to them and so Wi offers himself as sacrifice. Before the sacrifice takes place, the ice-gods are thawed. The ice age is ending. Wi and his companions leave the tribe and sail south but are caught in the rapids. It is at this point that Allan and Good awaken. Allan and Good discuss their adventure. They determine that Good was Moananga, Laleela was Luna Ragnall, and Allan's sometime companion Hans was the outcast Pag. Allan surmises that they are not actually experiencing past lives, but that the taduki drug has "the power of awakening the ancestral memory which has come down to us with our spark of life through scores of intervening forefathers." He also guesses that Wi and his companions dwelt in ice age Scotland, 500,000 or 50,000 years ago, and that Laleela came from southern Ireland or northern France