Anybody’s Pearls by Hulbert Footner

Dick Shemwell found himself in London, three thousand miles from home. He didn't have a penny and he didn't know a soul. He had tried honesty all his life; now he was ready to take a shot at crookedness. As he sat dejectedly in a hotel lobby, his face must have showed his thoughts, for five minutes later he had been invited to participate in an adventure that was to keep him that one jump ahead of violent death for some time to come.

Hired by a band of crooks to steal a pearl necklace from another crook who had stolen it from still another crook, he found himself whiled all over England, across the ocean and back again, the target of police and criminals alike, till a desperate battle solved the situation and set him right in the eyes of the law.