“I was thinking as I came along,” she said, as Jack Knebworth helped her off with her coat, “how very unreal everything is—I never dreamt I should be your guest to dinner, Mr. Knebworth.” “And I never dreamt you’d be worthy of such a distinction,” growled Jack. “And in five years’ time you’ll be saying, ‘Why on earth did I make such a fuss about being asked to a skimpy meal by that punk director Knebworth?’” He put his hand on her shoulder and led her into the room, and then for the first time she saw Michael, and that young man had a momentary sense of dismay when he saw her face drop. It was only for a second, and, as if reading his thoughts, she explained her sudden change of mien. “I thought we were going to talk nothing but pictures and pictures!” she said. “So you shall,” said Michael. “I’m the best listener on earth, and the first person to mention murder will be thrown out of the window.” “Then I’ll prepare for the flight!” she said good-humouredly. “For I’m going to talk murder and mystery—later!” Under the expanding influence of a sympathetic environment the girl took on a new aspect, and all that Michael had suspected in her was amply proven. The shyness, the almost frigid reserve, melted in the company of two men, one of whom she guessed was fond of her, while the other—well, Michael was at least a friend. “I have been doing detective work this afternoon,” she said, after the coffee had been served, “and I’ve made amazing discoveries,” she added solemnly. “It started by my trying to track the motor-car, which I guessed must have come into my street through a lane which runs across the far end. It is the only motor-car track I’ve found, and I don’t think there is any doubt it was my white-handed man who drove it. You see, I noticed the back tyre, which had a sort of diamond-shaped design on it, and it was fairly easy to follow the marks. Half-way up the lane I found a place where there was oil in the middle of the road, and where the car must have stood for some time, and there—I found this!” She opened her little handbag and took out a small, dark-green bottle. It bore no label and was unstoppered. Michael took it from her hand, examined it curiously and smelt. There was a distinctive odour, pungent and not unpleasing. “Do you recognize it?” she asked. He shook his head. “Let me try.” Jack Knebworth took the bottle from Michael’s hand and sniffed. “Butyl chloride,” he said quickly, and the girl nodded. “I thought it was that. Father was a pharmaceutical chemist, and once, when I was playing in his dispensary, I found a cupboard open and took down a pretty bottle and opened it. I don’t know what would have happened to me, only daddy saw me. I was quite a child at the time, and I’ve always remembered that scent.” “Butyl chloride?” Michael frowned.