He spoke with the utmost frankness, yet it came to Dot with an intuition she could not doubt that Hill did not believe him.  He returned the revolver to his pocket, but he kept a hold upon it, and he made no movement to take the hand Warden offered.

“We came to inspect the mine, not the men,” he said, shortly.  “Go back and tell them to clear out!”

Dot, mutely watching, saw Warden’s brows go up.  He had barely glanced at her.  “Oh, all right, sir,” he said, easily.  “They’ve hardly left off work yet.  I’ll let ’em know in good time.  But first I’ve got something to show you.  Come this way!”

He turned towards the main passage, but in a second, sharp and short, Fletcher’s voice arrested him.

“Warden!”

He swung on his heel.  “Well, sir?”

“You will do as I said—­immediately!” The words might have been uttered by a machine, so precise, so cold, so metallic were they.

Warden stood quite motionless, facing him, and it seemed to Dot that his eyes had become two blue flames, giving out light.  The pause that followed was so instinct with conflict that she thought it must end in some terrible outburst of violence.

Then, to her amazement, Warden smiled—­his candid, pleasant smile.  “Certainly, if you make a point of it,” he said.  “Perhaps you will walk up with me.  The strong-room is on our way, and while you are looking at the latest specimens I will carry out your orders.”

He turned back with the words, and led the way towards the distant lamp that glimmered in the wall.

Stiffly Hill turned to the girl beside him.  “Would you rather go back and wait for me?” he said.

“Oh, no!” she said, instantly.  “No; I am coming too.”

He said no more, but grimly stalked in the wake of Warden.

The latter moved quickly till he reached the place where the lamp was lodged in a niche in the wall.  Here he stopped, stooped, and fitted a key into a narrow door that had been let into the stone.  It opened outwards, and he drew aside, waiting for Hill.

“I will go and dismiss the men,” he said.  “May I leave you in charge till I come back?  They will not come this way.”

Hill paused on the threshold.  The lamp cast a dim light into the place, which was close and gloomy as a prison.

“There are two steps down,” said Warden.  “One of them is badly broken, but it’s worth your while to go in and have a look at our latest finds.  You had better go first, sir.  Be careful!”

He turned to depart with the words, still ignoring Dot.  She was close to Hill, and something impelled her to lay a restraining hand on his shoulder as he took the first step down.

What followed happened with such stunning swiftness that her memory of it ever afterwards was a confused jumble of impressions, like the wild course of a nightmare.