That night, lying on a cot in a tent shared with three Red Cross nurses, Mary did not fall asleep at once. The day had been a tremendous one. Much that war means had come crashing in upon her. At the field hospital she had seen what war could do to fine American boys. She had not known that she could feel so terribly sad and yet keep on smiling as she had done as she moved from cot to cot.

On the other hand she had never been quite so happy in her life as she was on realizing that she had helped them in a big way by bringing the quinine from America and that she could serve them still more by contacting their relatives and friends in America, when she got back.

“If I do get back,” she whispered. Watching Scottie down those Jap fighters who so richly deserved to die, she had realized as never before how easy it was for a life, just any life, her life, to go out like a match in a high wind.

“But my life must not go out yet,” she told herself, almost fiercely. “I have so much to do—”

She thought again of the messages she was carrying to America, and, strangely enough, of the roll of papyrus. She could not but feel that this roll was somehow very important.

Most important of all was the cargo. “It must go through!” she told herself. “We’ve only a little farther to go.”

After dinner that night she had sat on a log beside the stout-hearted Hop Sing. He had told her how his people had suffered through all those long years, of the speechless cruelties of the Japs, of homes destroyed, women and children reduced to slavery, and all the rest. And now help was coming—not enough yet—but more and more help.

What was the cargo they carried? Once again this question came up to intrigue but not to disturb her. Neither she nor Sparky had tried hard to guess the answer. “We shall know,” she assured herself. “It won’t be long now.”

Why were all those bombers heading for China in such haste? Would they help retake Burma and with it the Burma Road? Would they help defend Russia from possible Jap attack? Would they bomb Tokio? She could not guess the answer, but having visited that field hospital, she hoped as never before that they were headed for Tokio.

“And I’d love to go with them,” she told herself.

“But first the mountains,” she whispered. Scottie had told her of the pass, how during the monsoon period great storms went roaring up the sides of those highest mountains of the world.

“You can’t imagine it.” Those were his words. “Snow rising like smoke a thousand, two, three thousand feet from their peaks. A plane caught in the grip of such a storm is like a chip caught in a great whirlpool.”

Shivering at the very thought, Mary drew the covers close about her and at last fell fast asleep.

She was awake an hour before dawn and, disturbed by an overpowering sense of something wrong, drew on her clothes and walked outside. It was dark, gloomy, and chilly.

“Why did I leave my cozy bed?” she asked herself as she walked across the narrow airfield and then among the shadows of many planes to search out their own.

“There you are,” she whispered at last. “Good, old ship!”

To her surprise she saw that the door stood slightly ajar. Instantly her curiosity was aroused. Sparky, she knew, had not slept in the ship. For all that, he may have arisen early to look things over before the big day. That there were guards about she knew quite well, though she had not been challenged.

This, she told herself, was not strange. The moon was down. It was the darkest hour before dawn. There were more planes on the field than ever before in its history. No one would risk a light.

And yet, as she came close to their plane, she thought she caught a faint flicker inside its cabin. This did not startle her. Sparky was still in her mind. She would surprise him. It would be nice to spend an hour with him in their own ship before dawn on a day that should mean much to them.

With noiseless footsteps, she reached the plane, then climbed two rounds of the boarding ladder. Without a sound, she opened the door half way to peer into the darkness.

Did some good gremlin whisper, “Wait?” Who can say? She did wait. And then—she barely suppressed a gasp. The gleam of a tiny flashlight reflected by some bright object faintly illuminated a face within the cabin. It was not Sparky, not a man at all, but a woman. “The Woman in Black,” she thought, nearly falling from the ladder. She was sure that this was the woman who had fired a shot at her back there in the city.

Fascinated, she watched. The woman had torn the top from a corrugated box containing a unit of their precious cargo and was studying it intently.

“This,” Mary thought, “must be stopped.” Her heart beat a wild tattoo.

In her excitement, she must have made some slight sound. The light blinked out. There came the sound of rushing feet and before she could think or move, she was knocked from the ladder.

Landing on her head, she was knocked unconscious momentarily. But something made her mind fight back. When her senses started returning she could think and hear but could neither move nor speak.

She heard steady, approaching footsteps. “A guard,” she thought. “Oh! If I could only scream.”

With a violent effort she brought back her power of motion. Sitting up, she did scream. It was not a loud scream but enough for a voice said:

“Mary! What are you doing here? What has happened?”

“Sparky! Oh! I’m so glad!” She staggered to her feet.

“What is it?” He was near now.

“The Lady in Black! She was in the plane. She broke open a box. She knows the secret of our cargo. She—she’s a spy. Perhaps she has the roll of papyrus. She will escape and she must not!

“There!” Her voice rose as there came the sound of an airplane motor. “There’s a plane! Someone is with her. They must have stolen a plane. They will get away!”

Two guards came racing up. “Oh! It’s you!” the taller of the two said. “What’s up? What happened?”

“A woman spy was going over the cargo of our plane!” exclaimed Mary. “She saw too much. She may have taken something with her. We’ve got to catch her.”