When Lieutenant St. Vincent Halfhyde finds himself unexpectedly placed on shore on the half-pay list of the Royal Navy (following the debacle chronicled in Halfhyde on Zanatu), he decides to broaden his experience at sea on a merchantman bound for Sydney. His ship, the Aysgarth Falls, has an unsavory crew consisting primarily, it seems, of villains on the run from the police. Bad weather and outbreaks of fighting in the fo'c'sle herald the dangers ahead. In his efforts to uncover an illicit but lucrative deal made between the First Mate and a mysterious passenger to be picked up off Chile, Halfhyde is seized by unscrupulous captors who intend to deliver him into the clutches of his old enemy, Vice-Admiral Paulus von Merkatz. In an attempt to escape, the intrepid Halfhyde displays his naval training in an exciting chase across the high seas that climaxes in a clash in the treacherous shallows around Australia's Great Barrier Reef—where Halfhyde, at last, has the chance to try one of the most devious of stratagems.

This rousing adventure novel, set in the last days of the nineteenth century, once again proves Lieutenant Halfhyde to be one of the finest heroes ever to sail the high seas.