"Well?"

"I'm afraid he'll have some difficulty in persuading a judge not to sentence him to a considerable term of imprisonment."

"You'll have him arrested?"

"That is one of the regrettable but necessary preliminaries. _I_ shan't do anything."

"Except rub your hands?" she taunted.

"Not even that," he answered with supercilious patience. Then, seeing no profit in pursuing his conversation with Sylvia, he raised his voice to summon the detectives into the library. "We'll take this room first," he told her, "and then leave you undisturbed."

The detectives did not answer his summons immediately and he turned to fetch them from the hall. As he did so Sylvia saw him start with surprise. Two paces behind them, an unseen auditor of their conversation, stood Elsie Wylton. With a slight bow to Sylvia she entered the library and in the Seraph's interests requested Nigel to carry out his search as quickly and silently as possible.

"He's sleeping now," she said, "but he's been awake most of the night, so please don't disturb him. If you'll search the other rooms, I'll stay here and talk to Miss Roden."

Nigel retired with a nicely blended expression of amazement, humiliation and menace. As the ring of his footsteps grew gradually fainter, Elsie turned to Sylvia with outstretched hands.

"I'm so glad you've come," she began. "I was afraid...."

"How long has he been ill?" interrupted Sylvia in a voice of stern authority.

"It's some time now...."

"And how long have you been here?"

There was an unmistakable challenge in her tone. Elsie's thoughts had been so much concerned with the Seraph, her mind was so braced in readiness to meet Nigel's attack, that for the moment her own share in the quarrel with Sylvia was forgotten. The library door stood open; outside in the hall the amateur detective was directing operations.

"Some time," she answered with studied vagueness.

The simmering suspicions of eight ambiguous weeks were brought to boiling point in Sylvia's mind.

"How long?" she repeated.

Elsie leaned forward, a finger to her lips; before she could speak, the hall was filled with the creak of heavy boots and Nigel appeared in the doorway.

"She's not here," he announced.

"Who were you looking for?" Elsie inquired, masking her impatience at his untimely return.

"Your sister."

"Oh, I could have told you that."

"She _was_ here."

"Was she? What a pity you didn't come sooner! Why, Mr. Merivale invited you on Sunday, he told me. When he met you at your Club. I'm afraid you and the--er--gentleman outside have had your journey in vain."

Nigel's face flushed at the taunt and a certain uncomfortable prospect of polite criticism from the Criminal Investigation Department he had undertaken to educate.

"Not altogether," he said.

"No?"

"We've found Aintree."

"Ah; yes. I wanted to get him away to the sea, but he's not fit to move yet."

"He may have to."

"Not yet."

"A warrant for his arrest won't wait for him to get well--and away."

Nigel had never learned to disguise his feelings, and the threatening tone of his voice left no doubt in Elsie's mind that he was rapidly becoming desperate and would double his stakes to retrieve his earlier losings.

"So you're arresting him?" she said.

"He has obligingly piled up so much evidence against himself," he answered with a lift of the eyebrows.

"The same kind of evidence that led you to search these rooms for my sister?"

Nigel stood rigidly on his dignity.

"That will be forthcoming at the proper time and place."

"Unlike my sister," she rejoined in a mischievous undertone.

"Possibly she may be forthcoming when Aintree has been arrested."

A provoking smile came to disturb the last remnants of gravity on Elsie's face, lending dimples to her cheeks and laughter to her eyes.

"Possibly he won't be arrested," she remarked.

"You will prevent it?"

"I leave that to you."

"It's a matter for the police. I have no part or lot in it."

Elsie laughed unrestrainedly at his stiff dignity.

"You'll move heaven and earth to spare yourself a second humiliation like the present," she told him with a wise shake of the head. "It's ridiculous enough to search a man's rooms for a woman who isn't there, but you can't--you really can't arrest a man for harbouring a woman when there's no shred of evidence to show she was ever under the same roof."

Her mockery deepened the flush on Nigel's thin skin to an angry spot of red on either cheek.

"You forget that several of us visited this place the day after Miss Roden disappeared," he answered.

Elsie looked him steadily in the eyes.