Havoc by E. Phillips Oppenheim

Laverick, notwithstanding that the hour was becoming late, found an outfitter's shop in the Strand still open, and made such purchases as he could on Morrison's behalf. Then, with the bag ready packed, he returned to his rooms. Time had passed quickly during the last three hours. It was nearly nine o'clock when he stepped out of the lift and opened the door of his small suite of rooms with the latchkey which hung from his chain. He began to change his clothes mechanically, and he had nearly finished when the telephone bell upon his table rang.

"Who's that? " he asked, taking up the receiver.