The Mysterious Three by William le Queux

I dashed across to the door. It was locked. "Now tell me, what do you make of it? " Faulkner asked, when he had looked about the unfamiliar room and stared blankly out of the window.

"The solution seems pretty obvious," I said. "We've been drugged, or in some way made unconscious last night in Paulton's car, and driven here. I distinctly remember trying to keep awake. You gave me that cigar I smoked. Was it one of your own?"