hat we want."

"Come along, then. I'm ready."

CHAPTER II.

NICK IS BOLDLY CHALLENGED.

Nick knew the old Plummer mansion well. There is not a house to match it
in this country.

A hundred years and more ago it must have been the scene of strange
adventures. It was built, certainly, by one who did not expect a
peaceful and quiet life within it.

The thick stone walls, which look so unnecessarily massive, are really
double. There are secret passages and movable panels and trap-doors
enough in that house to hide a man, if a regiment of soldiers was after
him.

Evidently such a place offered every chance to shrewd criminals who
might have a motive for playing upon the superstitious beliefs of the
present proprietor.

Anybody who couldn't get up a respectable ghost in the old Plummer house
must be a very poor fakir.

The mere fact that all the doors and windows of a room were closed did
not prevent any person from going in or out at will, if he knew the
secrets of the house.

Nick thought of these things as he rode down there in the cars, and he
prepared himself for an interesting time, chasing bogus ghosts through
secret doors and panels.

But a surprise awaited him on his arrival. Colonel Richmond met him at
the door, and, by Nick's request, took him at once to the room from
which the articles had been stolen.

It was a modern room in a new part of the house.

Nick was entirely unprepared for this. He did not know that the colonel
had built any additions to the old mansion.

Colonel Richmond spoke of this remarkable feature of the case at once.

"If this thing had happened in the old part of the house," he said, "I
shouldn't have thought that it was anything but an ordinary robbery.

"Every room there can be entered in a secret manner, and no doubt there
are plenty of panels and passages which even I do not know.

"But there's nothing of the kind here. This wing was built under my eye,
and from my own design. I saw the beams laid and the floors nailed down.

"There is absolutely no way to enter the room in which we now stand
except by the two doors and the window.

"My nephew has told you about the robberies. You know that the doors and
the windows were practically guarded all the time.

"I don't believe that any mortal being could have got in here and got
out again without being seen.

"As for myself, I understand the case perfectly. My belief will seem
strange to you, because you do n