Room 15 was a plain, comfortable office in a plain, comfortable building on Clay Street, not far from the heart of the business district. It was on the second floor, and its one window opened to the rear, and faced a desolate assortment of back yards, rear walls, and rickety stairways. The floor had a worn carpet, and there was a desk, a few chairs and a shelf of law books. The place looked as though it had belonged to a lawyer in reduced circumstances, and I could but wonder how it had come into the possession of Doddridge Knapp, and what had become of its former occupant. I tried to thrust aside a spirit of melancholy, and looked narrowly to the opportunities offered by the room for attack and defense. The walls were solidly built. The window-casement showed an unusual depth for a building of that height. The wall had been put in to withstand an earthquake shock. The door opening into the hall, the door into Room 16, and the window furnished the three avenues of possible attack or retreat. The window upon examination appeared impracticable. There was a sheer drop of twenty feet, without a projection of any kind below it. The ledge was hardly an inch wide. The iron shutters by which it might be closed did not swing within ten feet of any other window. The one chance of getting in by this line was to drop a rope ladder from the roof. The door opening into Room 16 was not heavy, and the lock was a cheap affair. A good kick would send the whole thing into splinters. As it swung into Number 16 and not into my room it could not be braced with a barricade. Plainly it was not a good place to spend the night should Doddridge Knapp care to engineer another case of mysterious disappearance. The depression of spirits that progressed with my survey of the room deepened into gloom as I flung myself into the arm-chair before the desk, and tried to plan some way out of the tangle in which I was involved. How was I, single-handed, to contend against the power of the richest man in the city, and bring home to him the murder of Henry Wilton? I could look for no assistance from the police. The words of Detective Coogan were enough to show that only the most convincing proof of guilt, backed by fear of public sentiment, could bring the department to raise a finger against him. And how could I hope to rouse that public sentiment? What would my word count against that of the King of the Street?