The Wager was parted from Anson's squadron in the fierce storms off Cape Horn and struggled alone up the coast of Chile until she was driven against the rocks and sank. The survivors were soon involved in trouble of every kind. A surplus of rum, a disappearing stock of food, and a hard, detested captain soon drove them into drunkenness, mutiny, and bloodshed. After many months of privation, a handful of men made their way northward under the guidance of a band of Indians, at last finding safety in Valparaiso.

This saga of survival is the background to the adventures of two young men aboard the Wager: midshipman Jack Byron and his friend Tobias Barrow, an alarmingly naive surgeon's mate. Patrick O'Brian's many devoted readers will take particular interest in this story, as Jack and Toby form a kind of blueprint for Jack Aubrey and Stephen Maturin, the famed heroes of the great Aubrey/Maturin series to come.