he expected to hear,
the snoring of two men sound asleep.

Returning, he did not reenter his own room, but crossed the head of
the staircase to Robert's. He knocked lightly, and his brother's
"Hello, there! Come in!" reached Furneaux's ears. Not a word of the
remainder of the colloquy that ensued was lost on either of the
detectives.

"Sorry to disturb you, Bob," said Hilton, speaking from the doorway,
"but I thought you might not be in bed, and I've come to tell you that
Sylvia has just gone out by way of the drawing-room and is wandering
about the park."

"Sylvia! On her lonesome?" was Robert's astounded cry.

"Yes. It isn't right. I can't understand her behavior. I would have
followed her myself; but in view of your statement at dinner tonight,
I fancied it would save some annoyance if I entrusted that duty to
you."

"Look here, Hilton, old chap, are you really in earnest?"

"About Sylvia? Yes. I actually saw her. At this moment she is heading
for the lake. If you hurry you'll see her yourself."

"I say, it's awfully decent of you ... I take back a lot of what I
said tonight.... Of course, as matters stand, this is _my_ job....
Tell MacBain not to lock us out."

"I'll attend to that, if necessary. But don't mention me to Sylvia.
She might resent the notion of being spied on. Say that you, too, were
strolling about. You see, I heard the window being opened, and looked
out, naturally. Anyhow, drop me, and run this affair on your own."

Robert was slightly obfuscated--the fresh air quickly made him
worse--but he was sensible of having grossly misjudged Hilton.

"Right-O," he said, hurrying downstairs. "We'll have a talk in the
mornin'. Dash it! It's twelve o'clock. That silly kid! What's she
after, I'd like to know?"

Robert gone, Hilton returned to his own room and rang a bell. MacBain
came, and was asked if he was aware that Miss Sylvia had quitted the
house. MacBain gave his version of the story, and Fenley remarked that
he might leave the window unfastened until he made his rounds at one
o'clock.

Seemingly as an afterthought, Hilton mentioned his brother's open
door, and MacBain discovered that Mr. Robert was missing also.

By that time the detectives, without exchanging a word, had each
arrived at the same opinion as to the trend of events. Hilton Fenley
was remodeling his projects to suit an unforeseen development. No
matter what motive inspired Sylvia Manning's midnight ramble, there
could be n