It's high noon for the British empire. Royal Navy Lieutenant St. Vincent Halfhyde is once again despatched to Africa. This time his mission is to help capture a British traitor who carries secret blueprints of British warships. Assisted by a Scotland Yard detective and a handful of sailors, Halfhyde must outwit the clever Germans, who are determined to take the traitor and his secrets back to the Fatherland. Even the threat of flesh-eating ants and the snapping jaws of a monstrous crocodile can't stop Halfhyde from tackling his mission with British sang-froid and Victorian pluck.