When St. Vincent Halfhyde, captain of the steamer Taronga Park, is suddenly called to the Admiralty, he finds he has rather more to concern him than the cargo of textiles he was expecting to deliver to Valparaiso in Chile. The “request” is to take on board two “special” passengers: Mr. Mayhew of the Foreign Office and Detective Inspector Todhunter of the Metropolitan Police. Their secret mission is to rescue the bombastic Commander-in-Chief of the Chilean Navy, Admiral Watkiss—late of the British Navy—whose life is in danger. As the Taronga Park steams on towards Chile, feathers fly among the passengers. The alarming Mrs. Weder-Ublik, about to offer herself as a missionary to the South American Indians, finds the free and easy lifestyle of Halfhyde’s Australian girlfriend far from satisfactory, and the “missionary’s” life aboard is only tolerable with the support of the kindly Canon Rampling, who finds himself not totally at ease with the lady’s ministrations. Meanwhile in Valparaiso, a desperate Admiral Watkiss is unaware of the surprises in store for him when the Taronga Park docks and the politicians take over, with Britain treading a dangerous path between the fiery South Americans and the forbidding presence of the German Navy.