The suspense was unbearable. Finally the brothers tiptoed over and peered through the wide
crack.
Straightening up, Frank observed, 'Can't see anyone. We'd better go investigate.'
Fearful of stumbling in the inky darkness, the boys now turned on their flashlights, but shielded them with their hands. Cautiously they found their way to a door. It opened into a short
passageway which led down a narrow flight of steps.
Soon Frank and Joe were in another small hall. Ahead was a partially opened door, with light
streaming from it.
Every nerve taut, the young sleuths advanced. Frank edged up to the door and looked in.
'Well?' Joe hissed. To his utter astonishment Frank gave a low chuckle, and motioned him forward.
'For Pete's sake!' Joe grinned.
Inside, perched on a chipped grindstone, was a huge, white cat. Its tail twitched indignantly. An overturned lamp lay on a table.
The Hardys laughed in relief. 'Our noisemaker and lamplighter!' Frank said as the boys entered the room. 'The cat must have knocked over the lamp and clicked the switch.'
Although the room contained the gear mechanism and the shaft connected to the mill wheel, it
was being used as a living area by the present tenants. There were two overstuffed chairs, a
table, and a chest of drawers. On the floor, as if dropped in haste, lay a scattered newspaper.
'Let's search the rest of the mill before Markel and Docker get back,' Joe suggested. 'Nothing suspicious here.'
The Hardys started with the top story of the old building. There they found what was once the
grain storage room. Now it was filled with odds and ends of discarded furniture.
'I'm sure nothing's hidden here,' Frank said.
The other floors yielded no clues to what Docker and Markel's secret might be.
Frank was inclined to be discouraged. 'Maybe our big hunch is all wet,' he muttered.
Joe refused to give up. 'Let's investigate the cellar. Come on!'
The brothers went into the kitchen toward the basement stairway. Suddenly Joe gave a stifled
yell.
Something had brushed across his trouser legs. Frank swung his light around. The beam caught
two round golden eyes staring up at them.
'The white cat!' Joe said sheepishly.
Chuckling, the Hardys continued down into the damp, cool cellar. It was long and narrow, with
only two small windows.
Three walls were of natural stone and mortar. The fourth wall was lined with wooden shelves.
Frank and Joe played their flashlights into every corner.
'Hm.' There was a note of disappointment in Joe's voice. 'Wheelbarrow, shovels, picks-just ordinary equipment.'
Frank nodded. 'Seems to be all, but where are the old bricks and lumber that Ken said were stored here?'
'I'm sure the stuff was never intended for Elekton,' Joe declared. 'More likely the mill. But where? In a floor? We haven't seen any signs.'
Thoughtfully the boys walked over to inspect the shelves, which held an assortment of
implements. Frank reached out to pick up a hammer.
To his amazement, he could not lift it. A further quick examination revealed that all the tools were glued to the shelves.
'Joel' he exclaimed. 'There's a special reason for this-and I think it's camouflage!'
'You mean these shelves are movable, and the tools are fastened so they won't fall off?'
'Yes. Also, I have a feeling this whole section is made of the old lumber from Pritos' yard.'
'And the bricks?' Joe asked, puzzled.
His brother's answer was terse. 'Remember, this mill was used by settlers. In those days many places had hidden rooms in case of Indian attacks-'
'I get you!' Joe broke in. 'Those bricks are in a secret room! The best place to build one in this mill would have been the cellar.'
'Right,' agreed Frank. 'And the only thing unusual here is this shelf setup. I'll bet it's actually the entrance to the secret room.'
'All we have to do is find the opening mechanism,' Joe declared.
Using their flashlights, the boys went over every inch of the shelves. These were nailed to a
backing of boards. The Hardys pulled and pushed, but nothing happened. Finally, on the bottom
shelf near the wall, Frank discovered a knot in the wood. In desperation, he pressed his thumb hard against the knot.
There was the hum of a motor, and, as smoothly as though it were moving on greased rails, the
middle section of shelves swung inward.
'The door to the secret room!' Frank exulted.
Quickly the boys slipped inside the room and shone their flashlights around. The first thing they noticed was the flooring-recently laid bricks. Frank snapped on a light switch beside the
entrance.
The boys blinked in the sudden glare of two high-watt bulbs suspended from the low ceiling.
The next instant both spotted a small, handprinting press.
'The counterfeiters' workshop!' they cried out On a wooden table at the rear of the room were a camera, etching tools, zinc plates, and a large pan with little compartments containing various colors of ink. At the edge of the table was a portable typewriter.
Frank picked up a piece of paper, rolled it into the machine, and typed a few lines. Pulling it out, he showed the paper to Joe.
'The machine used to type the warning note Dad got!' Joe exclaimed excitedly. 'The counterfeiters must have thought he was on their trail.'
'And look here!' exclaimed Frank, his voice tense. A small pile of twenty-dollar bills lay among the equipment. 'They're fakes,' he added, scrutinizing the bills. 'They're the same as Chet's and Tony's.'
Joe made another startling discovery. In one corner stood a bow, with the string loosened and
carefully wound around the handgrip. A quiver of three hunting arrows leaned against the wall
nearby.
Excitedly Joe pulled one out. 'The same type that was fired at the girls,' he observed. 'This must belong to The Arrow!'
'Docker matches his description,' Frank pointed out. 'He easily could have colored his hair gray.'
The Hardys were thrilled at the irrefutable evidence all around them, 'Now we know why
Markel and Docker rigged the mill wheel-to give a warning signal when they're working in this
room!'
'Also, we have a good idea what was being sent to Peters in the envelopes-phony twenty-dollar bills!'
'Let's get Dad and Chief Collig here!' Joe urged, stuffing several of the counterfeits into a pocket.
As the boys turned to leave, the lights in the secret room went out. Frank and Joe froze. They realized the mill wheel had stopped turning.
'The signal!' Joe said grimly. 'Someone is coming!'
CHAPTER XIX
Underground Chase
THE HARDYS knew this was the signal for them to get out of the secret room-and fasti As they
hurried into the cellar, the lights came on again. With hearts beating faster, they started for the stairway. But before the boys reached it, they heard the mill door being unlocked, then heavy
