and a
little behind him Ela, and in T. B.'s hand was a pistol.

CHAPTER XX

T. B. Smith's inspection of the Secret House had yielded nothing
satisfactory; he had not expected that it would; he was perfectly
satisfied that the keen, shrewd brains which dominated the menage would
remove any trace there was of foul play.

"Where now?" asked Ela, as they turned out of the house.

"Back to Moor Cottage," said T. B., climbing into the car. "I am certain
that we are on the verge of our big discovery. There is a way out of the
cottage by some underground chamber, a way by which first Lady Constance
and then Poltavo were smuggled, and if it is necessary I am going to
smash every panel in those two ground floor rooms, but I will find the
way in to Mr. Farrington's mystery house."

For half an hour the two men were engaged in the room from which
Poltavo had been taken. They probed with centre bits and gimlets into
every portion of the room.

The first discovery that they made was that the oaken panels of the
chamber were backed with sheet iron or steel.

"It is a hopeless job; we shall have to get another kind of smith here
to tear down all the panellings," said T. B., lighting the gloom of his
despair with a little flash of humour.

He fingered the tiny locket absently and opened it again.

"It is absurd," he laughed helplessly. "Here is the solution in these
simple words, and yet we brainy folk from the Yard cannot understand
them!"

"God sav the Keng!" said Ela ruefully. "I wonder how on earth that is
going to help us."

A gasp from T. B. made him turn his face to his chief.

T. B. Smith was pointing at the piano. In two strides he was across the
room, and sitting on the stool he lifted the cover and struck a chord.
The instrument sounded a little flat and apparently had not received the
attention of a tuner for some time.

"I am going to play 'God save the King,'" said T. B. with a light in
his eyes, "and I think something is going to happen."

Slowly he pounded forth the familiar tune; from beginning to end he
played it, and when he had finished he looked at Ela.

"Try it in another key," suggested Ela, and again T. B. played the
anthem. He was nearing the last few bars when there was a click and he
leapt up. One long panel had disappeared from the side of the wall. For
a moment the two men looked at one another. They were alone in the
house, although a policeman was within call. The main force was