We had been home but a very short time when Sergeant Heath telephoned as he had promised. Vance went into the anteroom to answer the call and closed the door after him. A few minutes later he rejoined us and, ringing for Currie, ordered his hat and stick.

    "I'm running away for a while, old dear," he said to Markham. "In fact, I'm joining the doughty Sergeant at the Homicide Bureau. But I sha'n't be very long. In the meantime, I've ordered lunch for us here."

    "Damn the lunch!" grumbled Markham. "What are you meeting Heath for?"

    "I'm in need of a new waistcoat," Vance told him lightly.

    "That explanation's a great help," Markham snorted.

    "Sorry. It's the only one I can offer at present," Vance returned.

    Markham stared at him, disgruntled, for several minutes.

    "Why all this mystery?" he demanded.

    "Really, y' know, Markham, it's necess'ry." Vance spoke seriously. "I'm hoping to work out this beastly affair tonight."

    "For Heaven's sake, Vance, what are you planning?" Markham stood up in futile desperation.

    Vance took a pony of brandy and lighted a Régie. Then he looked at Markham affectionately.

    "I'm plannin' to entice the murderer into making one more bet—a losing bet...Cheerio." And he was gone.

    Markham fumed and fretted during Vance's absence. He showed no inclination to talk, and I left him to himself. He tried to interest himself in Vance's library, but evidently found nothing to hold his attention. Finally he lit a cigar and settled himself in an easy chair before the window, while I busied myself with some notes I was preparing for Vance.

    It was a little after half-past two when Vance returned to the apartment.

    "Everything is in order," he announced as he came in. "There are no horses running today, of course, but nevertheless I'm looking forward to a big wager being laid this evening. If the bet isn't placed, we're in for it, Markham. Every one will be present, however. The Sergeant, with Garden's help, has got in touch with all those who were present yesterday, and they will foregather again in the Gardens' drawing-room at six o'clock. I myself have left a message for Doctor Siefert, and I hope he gets it in time to join us. I think he should be there..." He glanced at his watch and, ringing for Currie, ordered a bottle of 1919 Montrachet chilled for our lunch.

    "If we don't tarry too long at table," he said, "we'll be able to hear the second half of the Philharmonic programme. Melinoff is doing Grieg's piano concerto, and I think it might do us all a bit of spiritual good. A beautiful climax, Markham—one of the most stirring in all music—simple, melodious, magistral. Curious thing about Grieg: it's taken the world a long time to realize the magnitude of the man's genius. One of the truly great composers..."

    But Markham did not go with us to the concert. He pleaded an urgent political appointment at the Stuyvesant Club, but promised to meet us at the Garden apartment at six o'clock. As if by tacit agreement, no word regarding the case was spoken during lunch. When we had finished Markham excused himself and departed for the club, while Vance and I drove to Carnegie Hall. Melinoff gave a competent, if not an inspired, performance, and Vance seemed in a more relaxed frame of mind as we started for home.

    Sergeant Heath was waiting for us when we reached the apartment.

    "Everything's set, sir," he said to Vance; "I got it here."

    Vance smiled a little sadly. "Excellent, Sergeant. Come into the other room with me while I get out of these Sunday togs."

    Heath picked up a small package wrapped in brown paper, which he had evidently brought with him, and followed Vance into the bedroom. Ten minutes later they both came back into the library. Vance was now wearing a heavy dark tweed sack suit; and on Heath's face was a look of smug satisfaction.

    "So long, Mr. Vance," he said, shaking hands. "Good luck to you." And he lumbered out.

    We arrived at the Garden apartment a few minutes before six o'clock. Detectives Hennessey and Burke were in the front hall. As soon as we were inside Burke came up and, putting his hand to his mouth, said to Vance sotto voce:

    "Sergeant Heath told me to tell you everything's all right. He and Snitkin are on the job."

    Vance nodded and started up the stairs.

    "Wait down here for me, Van," he said over his shoulder. "I'll be back immediately."

    I wandered into the den, the door of which was ajar, and walked aimlessly about the room, looking at the various pictures and etchings. One behind the door attracted my attention—I think it was a Blampied— and I lingered before it for several moments. Just then Vance entered the room. As he came in he threw the door open wider, half pocketing me in the corner behind it, where I was not immediately noticeable. I was about to speak to him, when Zalia Graem came in.

    "Philo Vance." She called his name in a low, tremulous voice.

    He turned and looked at the girl with a quizzical frown.

    "I've been waiting in the dining-room," she said. "I wanted to see you before you spoke to the others."

    I realized immediately, from the tone of her voice, that my presence had not been noticed, and my first impulse was to step out from the corner. But, in the circumstances, I felt there could be nothing in her remarks which would be beyond the province of my privilege of hearing, and I decided not to interrupt them.

    Vance continued to look squarely at the girl, but did not speak. She came very close to him now.

    "Tell me why you have made me suffer so much," she said.

    "I know I have hurt you," Vance returned. "But the circumstances made it imperative. Please believe that I understand more of this case than you imagine I do."

    "I am not sure that I understand." The girl spoke hesitantly. "But I want you to know that I trust you." She looked up at him, and I could see that her eyes were glistening. Slowly she bowed her head. "I have never been interested in any man," she went on—and there was a quaver in her voice. "The men I have known have all made me unhappy and seemed always to lead me away from the things I longed for..." She caught her breath. "You are the one man I have ever known whom I could—care for."

    So suddenly had this startling confession come, that I did not have time to make my presence known, and after Miss Graem finished speaking I remained where I was, lest I cause her embarrassment.

    Vance placed his hands on the girl's shoulders and held her away from him.

    "My dear," he said, with a curiously suppressed quality in his voice, "I am the one man for whom you should not care." There was no mistaking the finality of his words.

    Behind Vance the door to the adjoining bedroom opened suddenly, and Miss Beeton halted abruptly on the threshold. She was no longer wearing the nurse's uniform, but a plain tailored tweed suit, severe in cut.

    "I'm sorry," she apologized. "I thought Floyd—Mr. Garden—was in here."

    Vance looked at her sharply.

    "You were obviously mistaken, Miss Beeton."

    Zalia Graem was staring at the nurse with angry resentment.

    "How much did you hear," she asked, "before you decided to open the door?"

    Miss Beeton's eyes narrowed and there was a look of scorn in her steady gaze.

    "You perhaps have something to hide," she answered coldly, as she walked across the room to the hall door and went toward the drawing-room.

    Zalia Graem's eyes followed her as if fascinated, and then she turned back to Vance.

    "That woman frightens me," she said. "I don't trust her. There's something dark—and cruel—back of that calm self-sufficiency of hers...And you've been so kind to her—but you have made me suffer."

    Vance smiled wistfully at the girl.

    "Would you mind waiting in the drawing-room a little while?..."

    She gave him a searching look and, without speaking, turned and went from the den.

    Vance stood for some time gazing at the floor with a frown of indecision, as if loath to proceed with whatever plans he had formulated. Then he turned to the window.

    I took this opportunity to come out from my corner, and just as I did so Floyd Garden appeared at the hall door.

    "Oh, hello, Vance," he said. "I didn't know you had returned until Zalia just told me you were in here. Anything I can do for you?"

    Vance swung around quickly.

    "I was just going to send for you. Every one here?"

    Garden nodded gravely. "Yes, and they're all frightened to death—all except Hammle. He takes the whole thing as a lark. I wish somebody had shot him instead of Woody."

    "Will you send him in here," Vance asked. "I want to talk to him. I'll see the others presently."

    Garden walked up the hall, and at that moment I heard Burke speaking to Markham at the front door. Markham immediately joined us in the den.

    "Hope I haven't kept you waiting," he greeted Vance.

    "No. Oh, no." Vance leaned against the desk. "Just in time. Every one's here except Siefert, and I'm about to have Hammle in here for a chat. I think he'll be able to corroborate a few points I have in mind. He hasn't told us anything yet. And I may need your moral support."

    Markham had barely seated himself when Hammle strutted into the den with a jovial air. Vance nodded to him brusquely and omitted all conventional preliminaries.

    "Mr. Hammle," he said, "we're wholly familiar with your philosophy of minding your own business and keeping silent in order to avoid all involvements. A defensible attitude—but not in the present circumstances. This is a criminal case, and in the interest of justice to every one concerned, we must have the whole truth. Yesterday afternoon you were the only one in the drawing-room who had even a partial view down the hallway. And we must know everything you saw, no matter how trivial it may seem to you."

    Hammle, assuming his poker expression, remained silent; and Markham leaned forward glowering at him.

    "Mr. Hammle"—he spoke with cold, deadly calm—"if you don't wish to give us here what information you can, you will be taken before the Grand Jury and put under oath."

    Hammle gave in. He spluttered and waved his arms.

    "I'm perfectly willing to tell you everything I know. You don't have to threaten me. But to tell you the truth," he added suavely, "I didn't realize how serious the matter was." He sat down with pompous dignity and assumed an air which was obviously meant to indicate that for the time being he was the personification of law, order and truth.

    "First of all, then," said Vance, without relaxing his stern gaze, "when Miss Graem left the room, ostensibly to answer a telephone call, did you notice exactly where she went?"

    "Not exactly," Hammle returned; "but she turned to the left, toward the den. You understand, of course, that it was impossible for me to see very far down the hall, even from where I sat."

    "Quite." Vance nodded. "And when she came back to the drawing-room?"

    "I saw her first opposite the den door. She went to the hall closet where the hats and wraps are kept, and then came back to stand in the archway until the race was over. After that I didn't notice her either coming or going, as I had turned to shut off the radio."

    "And what about Floyd Garden?" asked Vance. "You remember he followed Swift out of the room. Did you notice which way they went, or what they did?"

    "As I remember, Floyd put his arm around Swift and led him into the dining-room. After a few moments they came out. Swift seemed to be pushing Floyd away from him, and then he disappeared down the hall toward the stairs. Floyd stood outside the dining-room door for several minutes, looking after his cousin, and then went down the hall after him; but he must have changed his mind, for he came back into the drawing-room in short order."

    "And you saw no one else in the hall?"

    Hammle shook his head ponderously. "No. No one else."

    "Very good." Vance took a deep inhalation on his cigarette. "And now let's go to the roof-garden, figuratively speaking. You were in the garden, waiting for a train, when the nurse was almost suffocated with bromin gas in the vault. The door into the passageway was open, and if you had been looking in that direction you could easily have seen who passed up and down the corridor." Vance looked at the man significantly. "And I have a feelin' you were looking through that door, Mr. Hammle. Your reaction of astonishment when we came out on the roof was a bit overdone. And you couldn't have seen much of the city from where you had been standing, don't y' know."

    Hammle cleared his throat and grinned.

    "You have me there, Vance," he admitted with familiar good-humor. "Since I couldn't make my train, I thought I'd satisfy my curiosity and stick around for a while to see what happened. I went out on the roof and stood where I could look through the door into the passageway—I wanted to see who was going to get hell next, and what would come of it all."

    "Thanks for your honesty." Vance's face was coldly formal. "Please tell us now exactly what you saw through that doorway while you were waiting, as you've confessed, for something to happen."

    Again Hammle cleared his throat.

    "Well, Vance, to tell you the truth, it wasn't very much. Just people coming and going. First I saw Garden go up the passageway toward the study; and almost immediately he went back downstairs. Then Zalia Graem passed the door on her way to the study. Five or ten minutes later the detective—Heath, I think his name is—went by the door, carrying a coat over his arm. A little later—two or three minutes, I should say— Zalia Graem and the nurse passed each other in the passageway, Zalia going toward the stairs, and the nurse toward the study. A couple of minutes after that Floyd Garden passed the door on his way to the study again—"

    "Just a minute," Vance interrupted. "You didn't see the nurse return downstairs after she passed Miss Graem in the passageway?"

    Hammle shook his head emphatically. "No. Absolutely not. The first person I saw after the two girls was Floyd Garden going toward the study. And he came back past the door in a minute or so..."

    "You're quite sure your chronology is accurate?"

    "Absolutely."

    Vance seemed satisfied and nodded.

    "That much checks accurately with the facts as I know them," he said. "But are you sure no one else passed the door, either coming or going, during that time?"

    "I would swear to that."

    Vance took another deep puff on his cigarette.

    "One more thing, Mr. Hammle: while you were out there in the garden, did any one come out on the roof from the terrace gate?"

    "Absolutely not. I didn't see anybody at all on the roof."

    "And when Garden had returned downstairs, what then?"

    "I saw you come to the window and look out into the garden. I was afraid I might be seen, and the minute you turned away I went over to the far corner of the garden, by the gate. The next thing I knew, you gentlemen were coming out on the roof with the nurse."

    Vance moved forward from the desk against which he had been resting.

    "Thank you, Mr. Hammle. You've told me exactly what I wanted to know. It may interest you to learn that the nurse informed us she was struck over the head in the passageway, on leaving the study, and forced into the vault which was full of bromin fumes."

    Hammle's jaw dropped and his eyes opened. He grasped the arms of his chair and got slowly to his feet.

    "Good Gad!" he exclaimed. "So that's what it was! Who could have done it?"

    "A pertinent question," returned Vance casually. "Who could have done it, indeed? However, the details of your secret observations from the garden have corroborated my private suspicions, and it's possible I may be able to answer your question before long. Please sit down again."

    Hammle shot Vance an apprehensive look and resumed his seat. Vance turned from the man and looked out of the window at the darkening sky. Then he swung about to Markham. A sudden change had come over his expression, and I knew, by his look, that some deep conflict was going on within him.

    "The time has come to proceed, Markham," he said reluctantly. Then he went to the door and called Garden.

    The man came from the drawing-room immediately. He seemed nervous, and eyed Vance with inquisitive anxiety.

    "Will you be so good as to tell every one to come into the den," Vance requested.

    With a barely perceptible nod Garden turned back up the hall; and Vance crossed the room and seated himself at the desk.