"Spying, then, as I thought. He has run us to earth."

And the other nodded. O'Hara took a turn across the room and back.

"In that case," he said, presently--"in that case, then, we must keep him prisoner here so long as we remain. That's certain." He spun round sharply with an exclamation. "Look here!" he cried, in a lower tone, "how about this fellow's friends? It isn't likely he's doing his dirty work alone. How about his friends, when he doesn't turn up to-night? If they know he was coming here to spy on us; if they know where the place is; if they know, in short, what he seems to have known, we're done for.

We'll have to run, get out, disappear. Hang it, man, d'you understand?

We're not safe here for an hour."

Captain Stewart's hands shook a little as he gripped them together behind him, and a dew of perspiration stood out suddenly upon his forehead and cheek-bones, but his voice, when he spoke, was well under control.

"It's an odd thing," said he--"another miracle, if you like--but I believe we are safe--reasonably safe. I--have reason to think that this fellow learned about La Lierre only last evening from some one who left Paris to-day to be gone a long time. And I also have reason to believe that the fellow has not seen the one friend who is in his confidence, since he obtained his information. By chance I met the friend, the other man, in the street this afternoon. I asked after this fellow whom we have here, and the friend said he hadn't seen him for twenty-four hours--was going to see him to-night."

"By the Lord!" cried the Irishman, with a great laugh of relief. "What luck! What monumental luck! If all that's true, we're safe. Why, man, we're as safe as a fox in his hole. The lad's friends won't have the ghost of an idea of where he's gone to.... Wait, though! Stop a bit! He won't have left written word behind him, eh? He won't have done that--for safety?"

"I think not," said Captain Stewart, but he breathed hard, for he knew well enough that there lay the gravest danger. "I think not," he said again.

He made a rather surprisingly accurate guess at the truth--that Ste.

Marie had started out upon impulse, without intending more than a general reconnaissance, and therefore without leaving any word behind him. Still, the shadow of danger uplifted itself before the man and he was afraid. A sudden gust of weak anger shook him like a wind.

"In Heaven's name," he cried, shrilly, "why didn't that one-eyed fool kill the fellow while he was about it? There's danger for us every moment while he is alive here. Why didn't that shambling idiot kill him?"

Captain Stewart's outflung hand jumped and trembled and his face was twisted into a sort of grinning snarl. He looked like an angry and wicked cat, the other man thought.

"If I weren't an over-civilized fool," he said, viciously, "I'd go up-stairs and kill him now with my hands while he can't help himself.

We're all too scrupulous by half."

The Irishman stared at him and presently broke into amazed laughter.

"Scrupulous!" said he. "Well, yes, I'm too scrupulous to murder a man in his bed, if you like. I'm not squeamish, but--Good Lord!"

"Do you realize," demanded Captain Stewart, "what risks we run while that fellow is alive--knowing what he knows?"

"Oh yes, I realize that," said O'Hara. "But I don't see why _you_ should have heart failure over it."

Captain Stewart's pale lips drew back again in their catlike fashion.

"Never mind about me," he said. "But I can't help thinking you're peculiarly indifferent in the face of danger."

"No, I'm not!" said the Irishman, quickly. "No, I'm not. Don't you run away with that idea! I merely said," he went oh--"I merely said that I'd stop short of murder. I don't set any foolish value on life--my own or any other. I've had to take life more than once, but it was in fair fight or in self-defence, and I don't regret it. It was your coldblooded joke about going up-stairs and killing this chap in his bed that put me on edge. Naturally I know you didn't mean it. Don't you go thinking that I'm lukewarm or that I'm indifferent to danger. I know there's danger from this lad up-stairs, and I mean to be on guard against it. He stays here under strict guard until--what we're after is accomplished--until young Arthur comes of age. If there's danger," said he, "why, we know where it lies, and we can guard against it. That kind of danger is not very formidable. The dangerous dangers are the ones that you don't know about--the hidden ones."

He came forward a little, and his lean face was as hard and as impa.s.sive as ever, and the bright blue eyes shone from it steady and unwinking.

Stewart looked up to him with a sort of peevish resentment at the man's confidence and cool poise. It was an odd reversal of their ordinary relations. For the hour the duller villain, the man who was wont to take orders and to refrain from overmuch thought or question, seemed to have become master. Sheer physical exhaustion and the constant maddening pain had had their will of Captain Stewart. A sudden shiver wrung him so that his dry fingers rattled against the wood of the chair-arms.

"All the same," he cried, "I'm afraid. I've been confident enough until now. Now I'm afraid. I wish the fellow had been killed."

"Kill him, then!" laughed the Irishman. "I won't give you up to the police."

He crossed the room to the door, but halted short of it and turned about again, and he looked back very curiously at the man who sat crouched in his chair by the window. It had occurred to him several times that Stewart was very unlike himself. The man was quite evidently tired and ill, and that might account for some of the nervousness, but this fierce malignity was something a little beyond O'Hara's comprehension. It seemed to him that the elder man had the air of one frightened beyond the point the circ.u.mstances warranted.

"Are you going back to town," he asked, "or do you mean to stay the night?"

"I shall stay the night," Stewart said. "I'm too tired to bear the ride." He glanced up and caught the other's eyes fixed upon him. "Well!"

he cried, angrily. "What is it? What are you looking at me like that for? What do you want?"

"I want nothing," said the Irishman, a little sharply. "And I wasn't aware that I'd been looking at you in any unusual way. You're precious jumpy to-day, if you want to know.... Look here!" He came back a step, frowning. "Look here!" he repeated. "I don't quite make you out. Are you keeping back anything? Because if you are, for Heaven's sake have it out here and now! We're all in this game together, and we can't afford to be anything but frank with one another. We can't afford to make reservations. It's altogether too dangerous for everybody. You're too much frightened. There's no apparent reason for being so frightened as that."

Captain Stewart drew a long breath between closed teeth, and afterward he looked up at the younger man coldly.

"We need not discuss my personal feelings, I think," said he. "They have no--no bearing on the point at issue. As you say, we are all in this thing together, and you need not fear that I shall fail to do my part, as I have done it in the past.... That's all, I believe."

"Oh, _as_ you like! As you like!" said the Irishman, in the tone of one rebuffed. He turned again and left the room, closing the door behind him. Outside on the stairs it occurred to him that he had forgotten to ask the other man what this fellow's name was--the fellow who lay wounded up-stairs. No, he had asked once, but in the interest of the conversation the question had been lost. He determined to inquire again that evening at dinner.

But Captain Stewart, left thus alone, sank deeper in the uncomfortable chair, and his head once more stirred and sought vainly for ease against the chair's high back. The pain swept him in regular throbbing waves that were like the waves of the sea--waves which surge and crash and tear upon a beach. But between the throbs of physical pain there was something else that was always present while the waves came and went.

Pain and exhaustion, if they are sufficiently extreme, can well nigh paralyze mind as well as body, and for some time Captain Stewart wondered what this thing might be which lurked at the bottom of him still under the surges of agony. Then at last he had the strength to look at it, and it was fear, cold and still and silent. He was afraid to the very depths of his soul.

True, as O'Hara had said, there did not seem to be any very desperate peril to face, but Stewart was afraid with the gambler's unreasoning, half-superst.i.tious fear, and that is the worst fear of all. He realized that he had been afraid of Ste. Marie from the beginning, and that, of course, was why he had tried to draw him into partnership with himself in his own official and wholly mythical search for Arthur Benham. He could have had the other man under his eye then. He could have kept him busy for months running down false scents. As it was, Ste. Marie's uncanny instinct about the Irishman O'Hara had led him true--that and what he doubtless learned from Olga Nilssen.

If Stewart had been in a condition and mood to philosophize, he would doubtless have reflected that seven-tenths of the desperate causes, both good and bad, which fail in this world, fail because they are wrecked by some woman's love or jealousy--or both. But it is unlikely that he was able just at this time to make such a reflection, though certainly he wondered how much Olga Nilssen had known, and how much Ste. Marie had had to put together out of her knowledge and any previous suspicions which he may have had.

The man would have been amazed if he could have known what a mountain of information and evidence had piled itself up over his head all in twelve hours. He would have been amazed and, if possible, even more frightened than he was, but he was without question sufficiently frightened, for here was Ste. Marie in the very house, he had seen Arthur Benham, and quite obviously he knew all there was to know, or at least enough to ruin Arthur Benham's uncle beyond all recovery or hope of recovery--irretrievably.

Captain Stewart tried to think what it would mean to him--failure in this desperate scheme--but he had not the strength or the courage. He shrank from the picture as one shrinks from something horrible in a bad dream. There could be no question of failure. He had to succeed at any cost, however desperate or fantastic. Once more the spasm of childish, futile rage swept over him and shook him like a wind.

"Why couldn't the fellow have been killed by that one-eyed fool?" he cried, sobbing. "Why couldn't he have been killed? He's the only one who knows--the only thing in the way. Why couldn't he have keen killed?"

Quite suddenly Captain Stewart ceased to sob and shiver, and sat still in his chair, gripping the arms with white and tense fingers. His eyes began to widen, and they became fixed in a long, strange stare. He drew a deep breath.

"I wonder!" he said, aloud. "I wonder, now."

XVI

THE BLACK CAT

That providential stone or tree-root, or whatever it may have been, proved a genuine blessing in disguise to Ste. Marie. It gave him a splitting headache for a few hours, but it saved him a good deal of discomfort the while his bullet wound was being more or less probed and very skilfully cleansed and dressed by O'Hara. For he did not regain consciousness until this surgical work was almost at its end, and then he wanted to fight the Irishman for tying the bandages too tight.

But when O'Hara had gone away and left him alone he lay still--or as still as the smarting, burning pain in his leg and the ache in his head would let him--and stared at the wall beyond his bed, and bit by bit the events of the past hour came back to him, and he knew where he was. He cursed himself very bitterly, as he well might do, for a bungling idiot.

The whole thing had been in his hands, he said, with perfect truth--Arthur Benham's whereabouts proved Stewart's responsibility or, at the very least, complicity and the sordid motive therefor.

Remained--had Ste. Marie been a sane being instead of an impulsive fool--remained but to face Stewart down in the presence of witnesses, threaten him with exposure, and so, with perfect ease, bring back the lost boy in triumph to his family.

It should all have been so simple, so easy, so effortless! Yet now it was ruined by a moment's rash folly, and Heaven alone knew what would come of it. He remembered that he had left behind him no indication whatever of where he meant to spend the afternoon. Hartley would come hurrying across town that evening to the rue d'a.s.sas, and would find no one there to receive him. He would wait and wait, and at last go home.

He would come again on the next morning, and then he would begin to be alarmed and would start a second search--but with what to reckon by?

n.o.body knew about the house on the road to Clamart but Mlle. Olga Nilssen, and she was far away.