It was some time after the models had been stolen in his absence that, in a taxicab, Locke, having gone from place to place which he knew Paul frequented, at last caught sight of him leaving a dance-hall of very ill repute.  Paul was just stepping into a car which whisked him off rapidly and Locke gave an order to his own driver to follow him.

They wove in and out of various streets and finally turned up the Drive, where, after a few minutes, Paul’s car came to a stop before a palatial apartment-house and Paul alighted.  Looking up and down the Drive and seeing nothing to cause him suspicion, Paul entered the house.

Locke carefully noted the address, then leaned back in his cab to await developments.

Paul was taken to the third floor and there was admitted to a gorgeous apartment.

“I thought you’d never get here,” languidly greeted the feline De Luxe Dora.

She led him to a chaise-longue seductively, taking care, however, that he should see a pile of unpaid bills that lay upon a table near it.

Paul was not entirely at his ease and wasted no time in coming to the point.

“Look here, Dora,” he began; “I know you can’t run this shack on air.  I got your note this morning.  I’ve been busy and I’ve got an idea.  I’ve made up my mind to take a couple of those inventions the company owns and sell them.  It means coin.”

Dora’s eyes gleamed avariciously.

“Be patient,” Paul added, “and I’ll have you swimming in gold.”

At this juncture three young fellows of the cabaret type, better known as “lounge lizards,” were admitted to the apartment.

Paul cast a glance at Dora which clearly spelled jealousy and reproach.  He knew the fellows.  In fact, there were few denizens of the underworld whom he did not know.  Concealing his vexation, he tried to greet them easily.

The fellows returned the salutation hastily.

“Say, Balcom,” hastened one of them, “some one is on your trail, shadowing you.”

Paul was startled and furious, but in this emergency it was Dora who thought out the plan of action.

“In a taxicab?” she repeated, as the others told what they had seen outside.  “Listen to me, Paul.  Go to the window and show yourself.  Then leave the house.  This fellow Locke will investigate—­and we’ll tend to the rest.”

Paul moved to the window, opened it, and stepped out on a small balcony.  Dora slipped to his side and for a moment they stood there gazing apparently at the view of the river.  Then they re-entered the apartment.

“Now go, Paul,” said Dora.  “Whoever this fellow is, we’ll handle him.”

Paul started to get his hat, then stopped and from his pocket drew out a small package.

“I was going to use this elsewhere,” he said, “but it might come in handy to—­”

Dora reached for the package, but Paul withdrew it hastily.

“Careful, Dora,” he admonished.  “There’s a small gas-bomb inside.”