So far, luck seemed in his favour. It was a non-stop train, and went past Down Street. At the next station, Dover Street, he saw her turn half round, and cast a furtive glance in his direction. She was evidently debating within herself if she would chance getting out there. While thus deliberating, the train re-started. At Piccadilly Circus there was a considerable exodus, as there always is. The process of disembarking was slow, owing to the number of passengers. They both emerged into Jermyn Street, and went along to the Haymarket. Here she looked round, apparently for a taxi, but there was not one in sight. It struck him, as he caught a side glimpse of her features, that she was looking worried and harassed. Evidently his persistent dogging had shaken her nerves. She walked slowly, with the deliberate gait of a person who was perturbed, and thinking hard. She entered a big drapery shop, where Mason was compelled to follow her for reasons. Had it been an ordinary kind of shop, he would have waited outside, till she came out. This particular establishment, however, had two entrances, one in Regent Street and one in Piccadilly. She knew this, of course, and would slip out of the one he was not watching. So he followed her in. Having bought a pair of long cream gloves she glanced furtively around, and then left the shop, passing into Regent Street. Afterwards she spent some time looking into the shop windows up and down that busy thoroughfare, ultimately returning to the Piccadilly Tube Station, where she took a ticket for Knightsbridge, Mason following all the while. Her face was wan and haggard with the relentless chase, but her eyes expressed indomitable resolution. They seemed to flash across at him as they sat in the same car the unspoken message: "I will outwit you yet." At Knightsbridge both watcher and watched ascended in the same lift, with its clanging lattice gate, and it was quite plain that Mrs Saxton was now in a quandary how to escape. In a careless attitude she passed from the street back into the booking-hall, where she pretended to idle up and down, as though awaiting someone. Now and then she looked up at the clock as though anxious and impatient. Mason believed her anxiety to be merely a ruse, but was both surprised and interested when a small ragged urchin entering the place suddenly recognised her, and handed her a note. She took it eagerly, and without examining it crushed it hurriedly into her little black silk bag, giving the little fellow a shilling, whereupon he thanked her and ran merrily out. Next instant Mason slipped forth after the lad in order to question him, leaving the woman safely in the booking-hall. In a few seconds he stopped the boy and asked good-humouredly who had given him the letter.