Finally Doctor Locke agreed that Zita might return with him, remain outside, and give the alarm if anything happened to him.  Thus, after many remonstrances, it was agreed, and Eva and Quentin went on to Brent Rock.

No one had molested Brent in the mean time.  The terror caused by the explosion, as well as the loss of Balcom, for the time, at least, had evidently cowed the emissary band.

While Eva made Brent comfortable, Locke went immediately to the laboratory, where he had something which he considered very important.

“Quentin,” remarked Eva, as she joined him, “your father spoke the truth, I believe, when he said that it was Balcom in the Automaton, But if that was the case, who is in it now?”

Locke shook his head dubiously.  “I give it up,” he replied.  “It’s too deep for me.  But whoever it is, he won’t trouble us long, I’ll wager.  I’ve been perfecting a special gun and an explosive-gas bullet.  No one can shoot the monster.  Nothing seems to stop it.  But this weapon, I think, will at last prove a match for it.”

Eva, who had always had the deepest interest in Quentin’s work, listened attentively as he explained in detail the working of the new weapon.

“And now we come to the actual loading of these asphyxiating-poison bullets,” concluded Quentin.  “I really must ask you, Eva, to go into another room, for it is dangerous work and you must not risk your life here.”

“But, Quentin,” remonstrated Eva, “we’ve risked our lives so often together that I have ceased to be afraid of anything.”

Quentin was insistent, and finally Eva agreed.

As Doctor Q and Zita neared the former’s laboratory, they saw that all the lights in the house were out.  Doctor Locke, against Zita’s advice, insisted on going in, and told his daughter to wait outside.  It was then that Zita disobeyed her father for the first time, for she flatly refused to be left behind.

“No,” she insisted.  “I found a father to-night and what we must risk we risk together.  It is no worse than the peril from which I once escaped.”

There was no reasoning with Zita, and they let themselves into the little yard and went up the back steps.  When they came to the door of the laboratory they listened intently.

There was no sound.  Then they mustered up courage and cautiously entered the room.  For a long time they stood quite still, not daring to move.  Finally Doctor Q suddenly lighted a match.

The room was in terrible confusion, as though cyclone-swept.

Doctor Locke turned on an electric bulb and the room was flooded with light.

Everywhere there were traces of the Automaton.  But the monster itself had left the place.  Doctor Locke crossed to the other door.  There was a sight that made them shudder.  The body of De Luxe Dora was still huddled in a heap on the floor.  She was quite dead.

But Doctor Locke had no time now to waste.  Moments were precious.  At any instant they might again be attacked.  Feverishly he began to search for the bottle containing the antidote.