Lieut. St. Vincent Halfhyde RN (inactive) is pressed back into service at the start of the Boer War, this time as skipper of the old square-rigged Glen Halladale, transport for a draft of hardened Dartmoor convicts bound to serve in South Africa.
Before the voyage, Halfhyde is offered a bribe to help smuggle gold bullion to South Africa. He reports the incident to the authorities, but after a series of mishaps Halfhyde discovers the gold is already hidden aboard. There is danger from the usual sources (the weather) and unusual ones (the restive convicts and a conspiracy that reaches into the Home Office). With his customary pluck and seamanship, Halfhyde works his way through the perils to safe harbor.