The woman was there, not a foot distant, her countenance a mask of suspicious determination.

“Go on!” she commanded in menacing accents.

He pulled the door open, flung out into the hallway, paused again at the mouth of the back pit of the stairway.

Behind him the woman snapped a switch; an electric bulb glared out of the darkness.  And P. Sybarite, peering down, started back with a gasp of amazement that was echoed in his ear.

On the stairs, halfway down, a man was crouching in a posture of frozen consternation:  a small electric pocket-lamp burning brilliantly in one hand, the other, lifted, grasping a weapon of some curious sort, in the eyes of P. Sybarite more than anything else like, a small black cannon:  a hatless man in evening clothes, his face half blotted out by a black mask that, enhancing the brightness of startled eyes gleaming through its peepholes, left uncovered only his angular muscular jaw and ugly, twisted mouth.

For a full minute (it seemed) not one of the three so much as drew breath; while through the haze of dumfounderment in P. Sybarite’s brain there loomed the fact that once again Kismet had played into his hands to save his face in thus lending material body and substance to the burglar of his desperate invention.

And then, as if from a heart of agony, the woman at his side breathed a broken and tortured cry: 

“You dog!  So it’s come to murder, has it?”

As if electrified by that ejaculation, P. Sybarite whipped up Penfield’s revolver and levelled it at the man on the stairs.

“Hands up!” he snapped.  “Drop that gun!”

The answer was a singular sound—­half a choking cough, half a smothered bark—­accompanied by a jet of fire from the strange weapon, and coincident with the tinkling of a splintered electric bulb.

Instantly the hall was again drenched in darkness but little mitigated by the light from the bedroom.

Heedless of consequences, in his excitement, P. Sybarite pulled trigger.  The hammer fell on an empty chamber, rose and fell half a dozen times without educing any response other than the click of metal against metal:  demonstrating beyond question that the revolver was unloaded.

From the hand of the marauder another tongue of flame licked out, to the sound of the same dull, bronchial cough; and a bullet thumped heavily into the wall beside P. Sybarite.

Enraged beyond measure, he drew back his worthless weapon and threw it with all his might.  And Kismet winged the missile to the firing arm of the assassin.  With a cry of pain and anger, this last involuntarily relaxed his grasp and, dropping his own pistol, stumbled and half fell, half threw himself down to the next floor.

As this happened, a white arm was levelled over the shoulder of P. Sybarite.

The woman took deliberate aim, fired—­and missed.

XII