ntly with Mark over the girl, and killed him in
sudden passion. Anything that happened after that would be self-defense.
I don't mean that I excuse it, but that I understand it. And I think
that Mark's dead body is in the passage now, and has been there since,
say, half-past two yesterday afternoon. And to-night Cayley is going to
hide it in the pond."

Bill pulled at the moss on the ground beside him, threw away a handful
or two, and said slowly, "You may be right, but it's all guess-work, you
know."

Antony laughed.

"Good Lord, of course it is," he said. "And to-night we shall know if
it's a good guess or a bad one."

Bill brightened up suddenly.

"To-night," he said. "I say, to-night's going to be rather fun. How do
we work it?"

Antony was silent for a little.

"Of course," he said at last, "we ought to inform the police, so that
they can come here and watch the pond to-night."

"Of course," grinned Bill.

"But I think that perhaps it is a little early to put our theories
before them."

"I think perhaps it is," said Bill solemnly.

Antony looked up at him with a sudden smile.

"Bill, you old bounder."

"Well, dash it, it's our show. I don't see why we shouldn't get our
little bit of fun out of it."

"Neither do I. All right, then, we'll do without the police to-night."

"We shall miss them," said Bill sadly, "but 'tis better so."

There were two problems in front of them: first, the problem of getting
out of the house without being discovered by Cayley, and secondly, the
problem of recovering whatever it was which Cayley dropped into the pond
that night.

"Let's look at it from Cayley's point of view," said Antony. "He may not
know that we're on his track, but he can't help being suspicious of
us. He's bound to be suspicious of everybody in the house, and more
particularly of us, because we're presumably more intelligent than the
others."

He stopped for a moment to light his pipe, and Bill took the opportunity
of looking more intelligent than Mrs. Stevens.

"Now, he has got something to hide to-night, and he's going to take good
care that we aren't watching him. Well, what will he do?"

"See that we are asleep first, before he starts out."

"Yes. Come and tuck us up, and see that we're nice and comfortable."

"Yes, that's awkward," said Bill. "But we could lock our doors, and then
he wouldn't know that we weren't there."

"Have you ever locked your door?"

"Never."

"No. And you