Mr. Hardy agreed that the purchase of lumber and bricks seemed odd, but he felt that until
more positive evidence could be obtained, it was best not to approach Elekton officials on the matter.
'I guess you're right, Dad,' said Frank. 'We might be way off base.'
The detective wished them luck on their sleuthing mission. The boys decided to make the trip in the Sleuth. They rode their motorcycles down to the boathouse, parked them, then climbed
aboard the new boat. Joe took the wheel and soon the sleek craft was cutting across the bay
toward the mouth of Willow River.
When they entered it, Joe throttled down and carefully navigated the stream. Meanwhile,
Frank shone his flashlight on the wooded banks.
'There's the cave-ahead!' he whispered.
Joe ran the boat astern a few yards and Frank dropped anchor. The brothers waded ashore,
carrying their shoes and socks.
When they reached the mouth of the cave, Joe said, 'Let's investigate this place first.'
They went into the cave and moved forward to the tunnel. One glance told them that the
tunnel had become impassable-it was filled with water.
'Must have been the cloudburst,' said Frank, as they emerged from the cave. 'We'll have to wait until the ground dries out. At least we can take a look through the woods and the area
around the mill for clues to the bowman.'
Shielding the lenses of their flashlights, so that the light beams would not be easily detected by anyone lurking in the vicinity, the boys began a thorough search of the wooded section. As they worked their way noiselessly uphill among the trees, the only sound was the eerie rattling the wind made in the leaves and branches.
Frank and Joe shone their lights beneath shrubs and rocks, and even crawled under some fallen
trees.
They found nothing suspicious. They were approaching the edge of the woods and could see
the outline of the mill beyond. The old wheel creaked and rumbled.
Suddenly Frank whispered hoarsely, 'Look! Here's something!'
Joe joined his brother, and together they examined the leather object Frank had picked up.
'An archer's finger guard,' he said.
'It may be a valuable clue to the arrow warning,' Joe said, as Frank pocketed the guard. 'Let's go up to the mill,' he proposed. 'Maybe the men there have seen something suspicious.'
As the boys crossed the clearing toward the gatehouse, they saw that it was in darkness.
'Probably everyone has gone to bed,' Frank remarked.
For a moment the brothers stood wondering what to do next. 'Something's missing,' Joe said in a puzzled voice. 'I have it! The mill wheel has stopped turning.'
'Maybe it was switched off for the night,' Frank observed.
The boys were eager to question the occupants, but decided not to awaken them.
'Let's walk around the mill,' said Frank, 'and look through the woods on the other side.'
The boys had just passed the north corner of the building when, with a creaking groan, the
wheel started to turn again.
'There must be something wrong with the mechanism,' Frank deduced. 'The wheel hasn't been used for so many years that adapting it to work the generator may have put a strain on
it.'
'We'd better let the men know it's acting up,' Joe said.
The boys retraced their steps to the mill door. As they reached it, the wheel stopped turning.
Frank and Joe stood staring off to their left where the mass of the motionless wheel was
outlined against the night sky.
'Spooky, isn't it?' Joe commented.
Frank nodded, and knocked on the door. There was no response. After a short wait, he knocked
again-louder this time. The sound echoed in the deep silence of the night. Still no one
answered.
The Hardys waited a while longer. Finally they turned away. 'Must be sound sleepers,' Joe commented.
'Well, maybe they'll discover what's wrong tomorrow.'
Frank and Joe were about to resume their search for clues when they heard a loud crashing
noise from the woods which bordered Willow River.
The boys dashed ahead to investigate. Entering the woods, they made their way stealthily
forward, flashlights turned off. Silently they drew near the river.
After a few minutes they stopped, and listened intently. The sound was not repeated.
'Must have been an animal,' Joe whispered.
Just then they heard a rustling sound behind them and turned to look. The next instant each
received a terrific blow on the back of the head. Both boys blacked out.
CHAPTER IX
Tracing a Slugger
WHEN Frank regained consciousness, his first thought was of his brother. He turned his
throbbing head and saw that Joe was lying next to him.
'Joe!' he exclaimed anxiously.
To his relief, Joe stirred and mumbled, 'W-what happened?'
'Someone conked us on the head-'
Frank broke off as he became aware of a gentle rocking motion. He sat up. Was he still dizzy or were they moving? When his mind and vision cleared, he knew they were certainly moving.
'Hey!' he said. 'We're on the Sleuth!'
Astonished, Joe raised himself and looked around. They were indeed aboard their boat-lying on
the foredeck and slowly drifting down Willow River toward the bay. The anchor lay beside
them.
'A fog's rolling in,' Frank said uneasily, observing white swirls of mist ahead. 'Let's start 'er up before visibility gets worse.'
The boys wriggled into the cockpit and Joe pressed the starter. It would not catch. While Joe
stayed at the controls, Frank climbed to the foredeck and lifted the cowling from the engine. He quickly checked to see if the distributor wires were in place. They were. There did not seem to be anything visibly wrong with the engine, but when he lifted the top off the carburetor, he
found it empty.
A quick check of the gas tank revealed the cause of the trouble. The tank had been drained.
'Fine mess we're in,' he mumbled. 'What was the idea?'
'The man who hit us on the head can answer that one,' Joe said bitterly. 'He sure did a complete job-even took both the oars!'
'We'll have to tow her,' Frank said tersely, 'to make more speed and guide her,'
While Joe stripped to his shorts, Frank quickly led a painter through one of the foredeck fair-leads.
'Take this painter,' Frank said, handing Joe the rope. 'Make it fast around your shoulder and swim straight ahead. I'll unhinge one of the battens and use it as a paddle and try to keep her straight. In a few minutes I'll change places with you.'
The Hardys knew that keeping a dead weight like the Sleuth moving in a straight line would be a tough job. However, with Joe swimming ahead and Frank wielding the batten, they managed to
make fairly steady progress.
It was slow, backbreaking work, and before they reached the bay, the boys had changed places
three times. Their heads were pounding more than ever from the physical strain. Also, the fog
had grown so dense that it was impossible to see very far ahead.
Frank, who was taking his turn in the water, did not know how much longer he could go on.
Suddenly Joe shouted from the boat, 'There's a light! Help! Help! Ahoy! Over here!' he directed at the top of
