Lt Commander Grimes arrives on the forgotten planet Sparta where humans had long ago settled and have since modelled their society on the ancient Greek city-state of Sparta. Indeed, Sparta, originally an early Federation colony, has been out of touch for so long the people have forgotten they’re a colony. Over time a civilisation based on war and violence and crude pleasures has developed. It is also a planet where human beings (all men) are produced by birth machines and women are unknown.
The story is told from the perspective of Brasidus, one of the small planet's policemen. Never having laid eyes on a woman, or imagined that such strange beings exist, he and most other residents of the planet Sparta think that the female crew of Grime's ship, including Margaret Lazenby (Grime's sometimes sex partner) are deformed men, and they can’t fathom what the peculiar bumps on their chests are.
Although Grimes and his crew have the best intentions during their stay on the planet they eventually manage to turn the whole society on its head. Horrific events unfurl and truths become known, setting in motion changes that have a profound effect on the Spartan society.
'Commander John Grimes, Federation Survey Service, should have been happy but he was not.' Although recently promoted, much to his surprise, Grimes finds himself consigned once again to being captain of a non-war ship. It doesn't help that his new vessel, Discovery (another Census ship) is a badly neglected rust-bucket. Worse still is the crew - a bunch of malcontents comprising the worse the Survey Service has to offer.
Before long a mutinous atmosphere begins to pervade the ship, with the situation spiraling downhill after Grimes is forced to cite the leader of the ship's marines, Major 'Mad' Swinton with the court-martial offence of murdering citizens from another planet. Grime's own misgivings about the voyage also manifest themselves through snatches of memory relating to the 'Wild Colonial Boy' and the ill-fated Bounty.
When the Commander and a few of his faithful crew are eventually dispatched into space aboard a tiny escape craft, he begins to understand how Captain William Bligh must have felt. Not only about the big black mark against his service record, but also about surviving against impossible odds.
Having resigned from the Federation Survey Service rather than face a court-martial for losing his ship in a mutiny (see The Big Black Mark), John Grimes finds himself stuck on the Planet Botany Bay and in urgent need of employment. His saviour comes in the form of the lofty Baroness Michelle d'Estang and her ship the Far Traveller. Built of gold and designed to be a rich woman's plaything the ship is piloted and run by an advanced computer known as Big Sister. And thus while Grimes might be the human Master (in so far as the ship's insurer is concerned), its Big Sister who rules the roost.
'Take one thoroughly spoiled, fabulously wealthy El Doradan baroness, one solid gold spaceyacht complete with almost human pilot-computer, one piratical space tramp captain, add the accident-prone John Grimes, late of the Federation Survey Service, stir and mix thoroughly-and the things that happen shouldn't happen to a Morrovian dog!' (1977 Hale edition).