After he had driven Adele home, he went to the police station and made his wishes known; but it was too late to see the chief constable, and the subordinate officer in charge did not wish to take the responsibility of detaching an officer for the purpose. It was only when Michael threatened to call the chief on the telephone that he reluctantly drew on his reserves and put a uniformed officer to patrol the street. Back again at Knebworth’s house, Michael examined the two articles which the girl had found. Butyl chloride was a drug and a particularly violent one. What use would the Head-Hunter have for that, he wondered. As for the handcuff, he examined it again. Terrific force must have been employed to snap the connecting links. This was a mystery to him, and he gave it up with a sense of annoyance at his own incompetence. Before going to bed he received a ’phone message from Inspector Lyle, who was watching Griff Towers. There was nothing new to report, and apparently life was pursuing its normal round. The inspector had been invited into the house by Sir Gregory, who had told him that Bhag was still missing. “I’ll keep you there to-night,” said Michael. “To-morrow we will lift the watch. Scotland Yard is satisfied that Sir Gregory had nothing to do with Foss’s death.” A grunt from the other end of the ’phone expressed the inspector’s disagreement with that view. “He’s in it somehow,” he said. “By the way, I’ve found a bloodstained derby hat in the field outside the grounds. It has the name of Chi Li Stores, Tjandi, inside.” This was news indeed. “Let me see it in the morning,” said Michael after long cogitation. Soon after breakfast the next morning the hat came and was inspected. Knebworth, who had heard most of the story from Michael, examined the new clue curiously. “If the coon wore Lawley’s hat when he arrived at Mr. Longvale’s, where, in the name of fate, did the change take place? It must have been somewhere between the Towers and the old man’s house, unless——” “Unless what?” asked Michael. He had a great respect for Knebworth’s shrewd judgment. “Unless the change took place at Sir Gregory’s house. You see that, although it is bloodstained, there are no cuts in it. Which is rum.” “Very rum,” agreed Mike ruefully. “And yet, if my first theory was correct, the explanation is simple.” He did not tell his host what his theory was. Accompanying Knebworth to the studio, he watched the char-à-banc drive off, wishing that he had some excuse and the leisure to accompany them on their expedition. It was a carefree, cheery throng, and its very association was a tonic to his spirits. He put through his usual call to London. There was no news. There was really no reason why he should not go, he decided recklessly; and as soon as his decision was taken his car was pounding on the trail of the joy wagon.