Already Eva had arrived at the Cliff House, had left her car, and was approaching on foot, just as Locke with the now thoroughly aroused emissaries swung into sight.

With a shout to the driver, the two in the back of the car leaped at Locke at once, and, as the car stopped, the chauffeur joined them.

Even prepared as he was, Locke was no match for three of them, and, fighting furiously, all four combatants rolled over and over as they came closer to the door of an old acid-mill that adjoined the Cliff House.

“We must keep him from saving the girl,” panted the leader of the emissaries to the others.

Inside the old building stood some huge tanks of acid, and as they rolled nearer and nearer to them it became evident that Locke was in their power.

Suddenly one emissary reached out and secured a coil of rope, which he unwound quickly.  The others, too, saw their chance.  It was fiendish.  Round and round they wound the rope until they had Locke well-nigh helpless.  Then one of them cast the end of the coil over a beam, all seized the end as it fell on the other side, and Locke found himself dangling head downward from the beam, suspended over the vat of acid.

They were about to drop him into it when one, more alert and more fiendish than the rest, cried out, “Look!”

Through a window now they could see Eva, and back of her the terrible figure of the Automaton, stalking.  She had walked directly into the trap, but the fight with Locke had delayed the emissaries.  Wildly now Eva was running over the lawn, full in the direction of the acid-room from the Cliff House.

“Quick!” directed the emissary.  “She’ll come in that door.  Fasten the rope on it.  Then his own sweetheart will drop him into the acid!”

It was only a matter of seconds, as the screams of Eva came closer and closer, for the emissaries to carry the rope and jam it into the door through which pretty soon Eva would run to take refuge from the pursuing Automaton.  Then they slunk back through a rear door, with muttered taunts to Locke, who struggled in the tangle of rope as he felt the stinging fumes of the acid below.

Outside, Eva, who had realized at last that it was a trap and had no thought that Locke might be anywhere about, fled toward the acid-room, while the emissaries hid, ready to seize her as she opened the door which was to plunge her lover into a horrible death in the acid seething below him.

CHAPTER XII

Locke’s case seemed at last hopeless.  The cruel ropes bit into his flesh and increased his agony, while the acrid fumes from the seething acid were slowly stupefying that keen brain of his.

Backward and forward like a huge pendulum his body swayed, and in an agony of suspense he watched the fatal rope.  With writhing body he swayed far out, and then he saw just one chance.