St. Vincent Halfhyde, recently separated from Her Majesty's Royal Navy, becomes the owner/master of the steamer Taronga Park, the first commercial vessel in the Halfhyde Line. In Victorian time, when coal-burning tramp steamers had replaced sleek clipper ships, Halfhyde's maiden voyage from Australia to Ireland was far from routine.
Severe storms and other dangers were commonplace as pre-Panama Canal sailors rounded Cape Horn. But when his cargo of machine parts turns out to be guns for the rebels in the West of Ireland, and the gun-running cargo owner boards in the Pacific and takes over the Taronga Park, only Halfhyde's grim determination to prevail carries the day.