There were very few people upon Platform Number Twenty-one of Liverpool StreetStation at a quarter to nine on the evening of April 2-possibly because the platform inquestion is one of the most remote and least used in the great terminus. The stationmaster, however, was there himself, with an inspector in attendance. A dark, thick-set man, wearing a long travelling ulster and a Homburg hat, and carrying in his hand a brownleather dressing-case, across which was painted in black letters the name MR. JOHN P.DUNSTER, was standing a few yards away, smoking a long cigar, and, to all appearanceabsorbed in studying the advertisements which decorated the grimy wall on the other sideof the single track. A couple of porters were seated upon a barrow which contained onesolitary portmanteau. There were no signs of other passengers, no other luggage. As amatter of fact, according to the time-table, no train was due to leave the station or to arriveat it, on this particular platform, for several hours.Down at the other end of the platform the wooden barrier was thrust back, and a porterwith some luggage upon a barrow made his noisy approach. He was followed by a tallyoung man in a grey tweed suit and a straw hat on which were the colours of a famouscricket club.The inspector watched them curiously. "Lost his way, I should think," he observed.The station-master nodded. "It looks like the young man who missed the boat train," heremarked. "Perhaps he has come to beg a lift."The young man in question made steady progress up the platform. His hands were thrustdeep into the pockets of his coat, and his forehead was contracted in a frown. As heapproached more closely, he singled out Mr. John P. Dunster, and motioning his porter towait, crossed to the edge of the track and addressed him."Can I speak to you for a moment, sir?"Mr. John P. Dunster turned at once and faced his questioner. He did so without haste-with a certain deliberation, in fact-yet his eyes were suddenly bright and keen. He wasneatly dressed, with the quiet precision which seems as a rule to characterise the travellingAmerican. He was apparently of a little less than middle-age, clean-shaven, broadshouldered, with every appearance of physical strength. He seemed like a man on wires, aman on the alert, likely to miss nothing