A big, powerful, red touring-car, with a shining brass bell on the front of it, was standing at the curb before our apartment late one afternoon as I entered.  It was such a machine as one frequently sees threading its reckless course in and out among the trucks and street-cars, breaking all rules and regulations, stopping at nothing, the bell clanging with excitement, policemen holding back traffic instead of trying to arrest the driver—­in other words, a Fire Department automobile.

I regarded it curiously for a moment, for everything connected with modern fire-fighting is interesting.  Then I forgot about it as I was whisked up in the elevator, only to have it recalled sharply by the sight of a strongly built, grizzled man in a blue uniform with red lining.  He was leaning forward, earnestly pouring forth a story into Kennedy’s ear.

“And back of the whole thing, sir,” I heard him say as he brought his large fist down on the table, “is a firebug—­mark my words.”

Before I could close the door, Craig caught my eye, and I read in his look that he had a new case—­one that interested him greatly.  “Walter,” he cried, “this is Fire Marshal McCormick.  It’s all right, McCormick.  Mr. Jameson is an accessory both before and after the fact in my detective cases.”

A firebug!—­one of the most dangerous of criminals.  The word excited my imagination at once, for the newspapers had lately been making much of the strange and appalling succession of apparently incendiary fires that had terrorised the business section of the city.

“Just what makes you think that there is a firebug—­one firebug, I mean—­back of this curious epidemic of fires?” asked Kennedy, leaning back in his morrischair with his finger-tips together and his eyes half closed as if expecting a revelation from some subconscious train of thought while the fire marshal presented his case.

“Well, usually there is no rhyme or reason about the firebug,” replied McCormick, measuring his words, “but this time I think there is some method in his madness.  You know the Stacey department-stores and their allied dry-goods and garment-trade interests?”

Craig nodded.  Of course we knew of the gigantic dry-goods combination.  It had been the talk of the press at the time of its formation, a few months ago, especially as it included among its organisers one very clever business woman, Miss Rebecca Wend.  There had been considerable opposition to the combination in the trade, but Stacey had shattered it by the sheer force of his personality.

McCormick leaned forward and, shaking his forefinger to emphasise his point, replied slowly, “Practically every one of these fires has been directed against a Stacey subsidiary or a corporation controlled by them.”

“But if it has gone as far as that,” put in Kennedy, “surely the regular police ought to be of more assistance to you than I.”

“I have called in the police,” answered McCormick wearily, “but they haven’t even made up their minds whether it is a single firebug or a gang.  And in the meantime, my God, Kennedy, the firebug may start a fire that will get beyond control!”