They had only to turn the corner of the tunnel to be sure.  Fernand had had the door of the tunnel slid noiselessly open, then, into the tunnel itself, smoking, slowly burning, pungent pieces of pine wood had been thrown, having been first soaked in oil, perhaps.  The tunnel was rapidly filling with smoke, and through the white drifts of it they looked into the lighted cellar beyond.  They would run out at last, gasping for breath and blinded by the smoke, to be shot down in a perfect light.  So much was clear.

“Now back to the wall and try to find that door,” said Ronicky.

Jerry had already turned.  In a moment they were back and tearing with their fingers at the sham wall, kicking loose fragments with their feet.

All the time, while they cleared a larger and larger space, they searched feverishly with the electric torch for some sign of a knob which would indicate a door, or some button or spring which might be used to open it.  But there was nothing, and in the meantime the smoke was drifting back, in more and more unendurable clouds.

“I can’t stand much more,” declared Jerry at length.

“Keep low.  The best air is there,” answered Ronicky.

A voice called from the mouth of the tunnel, and they could recognize the smooth tongue of Frederic Fernand.  “Doone, I think I have you now.  But trust yourselves to me, and all may still be well with you.  Throw out your weapons, and then walk out yourselves, with your arms above your heads, and you may have a second chance.  I don’t promise—­I simply offer you a hope in the place of no hope at all.  Is that a good bargain?”

“I’ll see you hung first,” answered Ronicky and turned again to his work at the wall.

But it seemed a quite hopeless task.  The surface of the steel was still covered, after they had cleared it as much as they could, with a thin, clinging coat of plaster which might well conceal the button or device for opening the door.  Every moment the task became infinitely harder.

Finally Jerry, his lungs nearly empty of oxygen, cast himself down on the floor and gasped.  A horrible gagging sound betrayed his efforts for breath.

Ronicky knelt beside him.  His own lungs were burning, and his head was thick and dizzy.  “One more try, then we’ll turn and rush them and die fighting, Jerry.”

The other nodded and started to his feet.  Together they made that last effort, fumbling with their hands across the rough surface, and suddenly—­had they touched the spring, indeed?—­a section of the surface before them swayed slowly in.  Ronicky caught the half-senseless body of Jerry Smith and thrust him inside.  He himself staggered after, and before him stood Ruth Tolliver!

While he lay panting on the floor, she closed the door through which they had come and then stood and silently watched them.  Presently Smith sat up, and Ronicky Doone staggered to his feet, his head clearing rapidly.