Tom and Jack, the latter especially, grew very fond of Bessie, but there seemed to be a mystery about her and something strange in her fear of her guardian.
When the two young men reached England, they lost sight, for a time, of their fellow passengers, but they were destined to meet them again under strange circumstances.
During one of their flights they landed near a lonely house behind the German lines. They were traveling in a Caudron, which contained them both, and on investigating the building after dark they found, to their surprise, that Bessie and her mother were kept there, prisoners of Carl Potzfeldt, who was a German spy.
Bessie and her mother were rescued and then departed for Paris, the latter to engage in Red Cross work, and the boys, remaining with their fellow aviators, longed for the time when they might see their friends once more.
But they had enlisted to help make the world safe for democracy, and they intended to stay until the task was finished. Over a year had elapsed since the sensational rescue of Bessie and her mother. The United States had entered the war and the Air Service boys were thinking that soon they might be able to join an American aviation service in France.
"What is it? What has happened?" Tom demanded of one of the aviators on the outskirts of the throng about the messenger. "Have we won a victory over the Germans?"
"No, but we're going to," was the answer. "Oh, boy! It's great! We're in it now sure! Hurray!"
"In it? What do you mean?" asked Jack.
"I mean that Uncle Sam has at last stepped over the line! He's sure enough on the side of the Allies now, and no mistake."
"You mean—" cried Tom.