The other protagonist, Mau, is an aboriginal native of the Nation who is first depicted alone at neighbouring Boys' Island, where he has hand-built a canoe to complete his initiation rite from boyhood into manhood.

Ermintrude, meanwhile, is travelling in a leisurely manner aboard a British schooner, the Sweet Judy, when mutineers, led by the ruthless First Mate Cox, are subdued and set adrift at sea, returning to the plot at a later time.

The tsunami has killed all the indigenous villagers of the Nation, except Mau, who now angrily rejects the gods and believes that his interrupted rite of passage has left him soulless.

Ermintrude timidly and sometimes recklessly interacts with Mau, but, eventually, the two start cooperating for mutual survival and establish some basic level of communication, though they are ignorant of each other's culture and language.

Three survivors from neighbouring islands arrive, including a cynical old priest named Ataba, who constantly derides Mau for his loss of faith.

Mau discovers the anchors in the Nation's lagoon alongside an additional, previously unknown stone, but Ataba attempts to destroy it, purportedly because it is heretical.

Mau, Daphne, Ataba, and their companions enter this cave and discover that the Nation is probably the oldest civilization on Earth, whose citizens once made astounding scientific progress with such creations as telescopes, eyeglasses, and even accurate star charts.

After exiting the cave, the group is confronted by two of Sweet Judy's villainous mutineers, who abruptly kill a spear-wielding Ataba and briefly abduct Daphne before she devises a cunning escape.

The new inhabitants of the Nation convince the arriving Cox and the cannibals to follow tradition by having the leaders of each side fight in hand-to-hand mortal combat, so as to avoid large-scale bloodshed.

Mau, wary of England's politics, is reluctant for the Nation to join the British Empire and instead requests that his homeland become a member of the scientific Royal Society.

He tells the children that from those days onward, thousands of scientists have visited the island, including Charles Darwin, Albert Einstein, Carl Sagan, and Richard Feynman.