Albert Lefioch, veteran of Verdun, stages a one-man strike and brings the whole of France's canal system to a halt. Since the barge traffic includes a vital consignment of secret oil for Concorde, Mogul is deeply concerned.
Meanwhile, in England, another old man succeeds in stopping the Mogul refinery which produces the oil.

Giant submarine tankers have been a dream in the oil industry for years. Now, they are not only possible but necessary-to ship oil out of Alaska under the ice.

Mogul's experiments have gone well. Now Stead, Thornton, and Izard visit their submarine - not in Alaska but in the Caribbean. Even there, though, things can go dangerously wrong - as Stead finds on his first underwater dive.