Pat stared at the intruder in a mingling of embarrassment, perplexity, and indignation. She felt her cheeks reddening as the latter emotion gained the dominance of her mood.

"Well!" she snapped. "What do you want?"

"I thought I'd walk home with you," Mueller said amiably.

"Walk home with me! Please explain that!" She grasped the arm of Nicholas Devine, who had risen angrily at the interruption. "Sit down, Nick, I know the fellow."

"So should he," said Mueller. "Sure; I'll explain. I'm on a job for Dr. Horker."

"Spying on me for him, I suppose!" taunted the girl.

"No. Not on you."

"He means on me," said Nick soberly. "You can't blame him, Pat. And perhaps you had better go home; we've finished here. There's nothing more we can do or say."

"Very well," she said, her voice suddenly softer. "In a moment, Nick." She turned to Mueller. "Would you mind telling me why you waited until now to interfere? We've been here two hours, you know."

"Sure I'll tell you. I got no orders to interfere, that's why."

"Then why did you?" queried Pat tartly.

"I didn't until I saw him there"—he nodded at Nick—"put his arms around you. Then I figured, having no orders, it was time to use my own judgment."

"If any!" sniffed the girl. She turned again to Nick; her face softened, became very tender. "Honey," she murmured huskily, "I guess it's good-bye now. I'll be fighting with you; you know that."

"I know that," he echoed, looking down into her eyes. "I'm almost happy, Pat."

"When'll you go?" she whispered in tones inaudible to Mueller.

"I don't know," he answered, his voice unchanged. "I'll have to make some sort of preparations—and I don't want you to know."

She nodded. She gazed at him a moment longer with tear-bright eyes. "Good-bye, Nick," she whispered. She rose on tiptoe, and kissed him very lightly on his lips, then turned and walked quickly away, with Mueller following behind.

She walked on, ignoring him until he halted beside her at the crossing of the Drive. Then she gave him a cold glance.

"Why is Dr. Carl having him watched?" she asked.

Mueller shrugged. "The ins and outs of this case are too much for me," he said. "I do what I'm paid to do."

"You're not watching him now."

"Nope. Seemed like the Doctor would think it was more important to get you home."

"You're wasting your time," she said irritably as the lights changed and they stepped into the street. "I was going home anyway."

"Well, now you got company all the way." Mueller's voice was placid.

The girl sniffed contemptuously, and strode silently along. The other's presence irritated her; she wanted time and solitude to consider the amazing story Nicholas Devine had given her. She wanted to analyze her own feelings, and most of all she wanted just a place of privacy to cry out her misery. For now the loss of Nicholas Devine had changed from a fortunate escape to a tragedy, and liar, madman, or devil, she wanted him terribly, with all the power of her tense little heart. So she moved as swiftly as she could, ignoring the silent companionship of Mueller.

They reached her home; the light in the living room window was evidence that the bridge game was still in progress. She mounted the steps, Mueller watching her silently from the walk; she fumbled for her key.

Suddenly she snapped her hand-bag shut; she couldn't face her mother and the two spinster Brocks and elderly, inquisitive Carter Henderson. They'd suggest that she cut into the game, and they'd argue if she refused, and she couldn't play bridge now! She glanced at the impassive Mueller, turned and crossed the strip of lawn to Dr. Horker's residence, where the light still glowed in the library, and rang the bell. She saw the figure on the sidewalk move away as the shadow of the Doctor appeared on the lighted square of the door.

"Hello," boomed the Doctor amiably. "Come in."

Pat stalked into the library and threw herself angrily into Dr. Horker's particular chair. The other grinned, and chose another place.

"Well," he said, "What touched off the fuse this time?"

"Why are you spying on my friends?" snapped the girl. "By what right?"

"So he's spotted Mueller, eh? That lad's diabolically clever, Pat—and I mean diabolic."

"That's no answer!"

"So it isn't," agreed the Doctor. "Say it's because I'm acting in loco parentis."

"And in loco is as far as you'll get, Dr. Carl, if you're going to spy on me!"

"On you?" he said mildly. "Who's spying on you?"

"On us, then!"

"Or on us?" queried the Doctor. "I set Mueller to watch the Devine lad. Have you by some mischance broken your promise to me?"

Pat flushed. She had forgotten that broken promise; the recollection of it suddenly took the wind from her sails, placed her on the defensive.

"All right," she said defiantly. "I did; I admit it. Does that excuse you?"

"Perhaps it helps to explain my actions, Pat. Don't you understand that I'm trying to protect you? Do you think I hired Mueller out of morbid curiosity, or professional interest in the case? Times aren't so good that I can throw money away on such whims."

"I don't need any protection. I can take care of myself!"

"So I noticed," said the Doctor dryly. "You gave convincing evidence of it night before last."

"Oh!" said the girl in exasperation. "You would say that!"

"It's true, isn't it?"

"Suppose it is! I don't have to learn the same lesson twice."

"Well, apparently once wasn't enough," observed the other amiably. "You walked into the same danger tonight."

"I wasn't in any danger tonight!" Suddenly her mood changed as she recalled the circumstances of her parting with Nicholas Devine. "Dr. Carl," she said, her voice dropping, "I'm terribly unhappy."

"Lord!" he exclaimed staring at her. "Pat, your moods are as changeable as my golf game! You're as mercurial as your Devine lad! A moment ago you were snapping at me, and now I'm suddenly acceptable again." He perceived the misery in her face. "All right, child; I'm listening."

"He's going away," she said mournfully.

"Don't you think that's best for everybody concerned? I commend his judgment."

"But I don't want him to!"

"You do, Pat. You can't continue seeing him, and his absence will make it easier for you."

"It'll never be easier for me, Dr. Carl." She felt her eyes fill. "I guess I'm—just a fool about him."

"You still feel that way, after the experience you went through?"

"Yes. Yes, I do."

"Then you are a fool about him, Pat. He's not worth such devotion."

"How do you know what he's worth? I'm the only one to judge that."

"I have eyes," said the Doctor. "What happened tonight to change your attitude so suddenly? You were amenable to reason yesterday."

"I didn't know yesterday what I know now."

"So he told a story, eh?" The Doctor watched her serious, troubled features. "Would you mind telling me, Honey? I'm interested in the defense mechanisms these psychopathic cases erect to explain their own impulses to themselves."

"No, I won't tell you!" snapped Pat indignantly. "Psychopathic cases! We're all just cases to you. I'm a case and he's another, and all you want is our symptoms!"

Doctor Horker smiled placatingly into her face. "Pat dear," he said earnestly, "don't you see I'd give my eyes to help you? Don't take my flippancies too seriously, Honey; look once in a while at the intentions behind them." He continued his earnest gaze.

The girl returned his look; her face softened. "I'm sorry," she said contritely. "I never doubted it, Dr. Carl—it's only that I'm so—so torn to pieces by all this that I get snappy and irritable." She paused. "Of course I'll tell you."

"I'd like to hear it."

"Well," she began hesitantly, "he said he was two personalities—one the character I knew, and one the character that we saw Saturday night. And the first one is—well, dominant, and fights the other one. He says the other has been growing stronger; until lately he could suppress it. And he says—Oh, it sounds ridiculous, the way I tell it, but it's true! I'm sure it's true!" She leaned toward the Doctor. "Did you ever hear of anything like it? Did you, Dr. Carl?"

"No." He shook his head, still watching her seriously. "Not exactly like that, Honey. Don't you think he might possibly have lied to you, Pat? To excuse himself for the responsibility of Saturday night, for instance?"

"No, I don't," she said defiantly.

"Then you have an idea yourself what the trouble is? I judge you have."

"Yes," she said in low tones. "I have an idea."

"What is it?"

"I think he's possessed by a devil!" said the girl flatly.

A quizzical expression came into the Doctor's face. "Well, of all the queer ideas that harum-scarum mind of yours has ever produced, that's the queerest!" He broke into a chuckle.

"Queer, is it?" flared Pat. "I don't think you and your mind-doctors know as much as a Swahili medicine-man with a mask!"

She leaped angrily to her feet, stamped viciously into the hall.

"Devil and all," she repeated, "I love him!"

"Pat!" called the Doctor anxiously. "Pat! Where are you going, child?"

"Where do devils live?" Her voice floated tauntingly back from the front door. "Hell, of course!"