But soon—very soon, indeed—German undersea craft were to strike a more severe blow at allied shipping, carrying, for the moment, the war in all its horrors to the very door of America. While the United States was arming and equipping its millions to send across the sea to destroy the kaiser and German militarism, these enemy undersea craft were crossing the Atlantic determined to reap a rich harvest upon American, allied and neutral shipping off the American coast.
And the blow was to be delivered without warning—almost.
When the U.S.S. Plymouth, under Jack's command, returned to Liverpool, the captain of the vessel, having somewhat recovered, came aboard and relieved Jack of command.
"I'm obliged for your services, Captain," he said, "but I'll take charge of the old scow again myself, with your leave."
Jack and Frank went ashore, where, at their hotel, they received a brief telegram from Lord Hastings. It read as follows:
"Return to Dover at once. Important."
"Now I wonder what is up," said Frank after reading the message.
"The simplest way to find out," replied Jack, "is to go and see."