But Willet, who was of a jealous disposition, waved him sternly away. “After marriage, if you like, my lad, not before. You’re too good-looking, and not old enough. Never introduce your young lady to a pal. No offence, of course. You’d do the same in my place, or you haven’t got the headpiece I give you credit for.”

Johnson admitted meekly that in the case of an attractive young woman it was wise to take precautions. They parted on the understanding that they would meet at the same place two nights later.

They met at the time appointed, and there was an almost offensive air of triumph about Mr Willet’s demeanour that argued good things. He started by ordering refreshment.

“Now to business,” he said, in his sharp, slangy way. “I’ve pumped Lily all right, and this job seems as easy as falling off a house. No letters have come from the lady, or gone to her, since she left, but—” he made a long pause here. “Every week a letter comes to Mrs Adair with the Weymouth postmark on it and every week Mrs Adair writes to a Mrs Marsh, whom Lily never heard of, and the letter is addressed to the Weymouth post-office. The writing on the envelope that comes to Mrs Adair is not Lady W.’s. Do you tumble?”

“It’s a hundred chances to one that her ladyship is at Weymouth, and her maid addresses the envelope,” was Johnson’s answer.

“I say ditto. Mrs Adair’s letter is posted every Thursday. To-day is Wednesday. Put yourself in the Weymouth train to-morrow, keep a watch on the post-office next morning, and the odds are that letter will be fetched by Lady Wrenwyck, or her maid.”

“Thanks to the portrait I know the mistress, but I don’t know the maid. Describe her to me.”

Mr Willet produced a piece of paper and pencil. “I’m a bit of an artist in my spare time. I’ll draw her for you so exactly that you can’t mistake her.”

He completed the sketch and handed it to his cousin. Later, they parted with mutual expressions of good will.

Friday morning saw Johnson prowling round the Weymouth post-office. He had to wait some time, but his patience was rewarded—he saw both Lady Wrenwyck and her maid.