This fast moving adventure story is set in the late 1830's. James Forester has a score to settle with a certain Captain Spence, and to this end he volunteers for service in a Royal Navy ship under an assumed name. Although his objective is challenging enough, he gradually discovers that he is not the only one with a mission, and soon becomes involved in a complex web of intrigue involving criminals on both sides of the Atlantic. The action moves from England to the eastern seaboard of the US and thence to California. There he realises that the real struggle has been within himself: a problem that he finally overcomes.