Burton stooped and entered. He found himself in a spacious chamber, dimly lit through the doorway and the hurdles stretched across the farther end. To him, coming from the brilliant sunlight, the interior was at first impenetrably dark; but as his eyes became accustomed to the dimness, he saw the gun, clean, silent, on a bed of concrete; rows of shells placed in recesses in the walls; and the opening of a tunnel.
"That leads to our dug-out," said Cay. "We'll find some one there."
A few steps through the tunnel brought them to a large cave-like room, furnished with table and chairs, four bunks and a store cupboard. Two officers were taking a late luncheon.
"Let me introduce Burton, V.C., D.S.O., one of our spotters," said Cay. "Captain Adams, Mr. Mortimer."
"Hullo, Burton? So it's you. How d'ye do?" said the captain, shaking hands. "Haven't seen you for an age. Have a drink?"
"A cosy little place, this," said Burton, as he quaffed a mug of cider.
"H'm! Pretty fair. We're proof against anything but a 'Jack Johnson.' They haven't discovered us yet. We've had a few pip-squeaks and four-twos, by accident. We make better practice, I think."
"You missed a chance this morning."
"How's that?"
"Well, that mill, you know, just across the way--the Huns' divisional headquarters."