'It's a funny way to deliver a message,' Frank commented.
'Very suspicious, if you ask me!' Aunt Gertrude snapped.
Suddenly they all noticed that Mr. Hardy was frowning at the contents of the envelope-a plain
piece of white paper.
'What does it say, Fenton?' Mrs. Hardy asked anxiously.
He read the typed message: ' 'Drop case or else danger for you and family! '
There was silence for a moment, then Aunt Gertrude exclaimed, 'I knew it! We can't get a
decent night's sleep with three detectives in the family! I just know there's real trouble
brewing!'
Although she spoke tartly, the others realized Miss Hardy was concerned, as always, for her
brother's safety.
'Now, don't worry, Gertrude,' Fenton Hardy said reassuringly. 'The boys and I will be on guard against any danger. This note probably is the work of a harmless crank.'
Aunt Gertrude tossed her head as though she did not believe this for a moment.
'Let's all look around for clues to the person on the bike,' Frank suggested.
Flashlights were procured, and the entire family searched the grounds thoroughly on both sides of the stoop and the walk. As Frank and his aunt neared the end of the front walk, Miss Hardy
cried out, 'There's something-next to that bush.'
Frank picked up the object. 'A bicycle pedal!' he exclaimed. 'Aunty, this is a terrific clue! I think we have four detectives in the family!'
His aunt forced a rather embarrassed smile.
'The pedal must've fallen off the bike Joe saw,' Frank said. 'That's why it swerved.'
Back in the house, the family gathered in the kitchen. They were too excited to go back to bed immediately, and the boys were eager to question their father. They all had cookies and
lemonade.
'What case did the warning refer to?' Joe asked Mr. Hardy.
'I can't be sure,' the detective replied slowly.
Again the boys wondered about Mr. Hardy's secret case, and longed to know what it involved.
'Maybe the threat is connected with that one,' Frank thought. Before the boys went to sleep, they decided to track down the pedal clue early the next morning.
Right after breakfast, Chet telephoned. He told Frank, who took the call, that his sister Iola and her friend Callie Shaw had offered to pack lunch if they could go along on the picnic.
'Swell,' Frank said enthusiastically. Callie was his favorite date. 'In the meantime, how'd you like to do some sleuthing with us?'
'Sure! What's up?'
Frank quickly told Chet about the excitement of the previous night. 'Meet us here as soon as you can.'
When Frank and Joe informed Mr. Hardy of their plan to trace the pedal, he nodded approval.
'I must go out of town for a short while,' he said. 'But first, I'd like to examine the warning note in the lab.'
The boys went with him to their fully equipped laboratory over the garage. Mr. Hardy dusted
the note carefully, but when he blew the powder away, there was no sign of a fingerprint.
Holding the note up to the light, Mr. Hardy said, 'There's no watermark. Of course, this is not a full sheet of paper.'
'Dead end, so far.' Joe frowned, 'If we could only locate the typewriter this message was written on-'
Shortly after Mr. Hardy had driven off in his sedan, Chet arrived. 'Where to, fellows?' he asked as they set off in the Queen.
'Center of town,' Joe replied.
On the way, the brothers briefed Chet on their plan, which was to make inquiries at all the
bicycle supply stores. In the first four they visited, Frank showed the pedal and asked if there had been any requests for a replacement that morning. All the answers were negative. Finally,
at the largest supply store in Bayport, they obtained some helpful
information.
'This particular pedal comes from a bike made in Belgium,' the proprietor said. 'There isn't a store in town that carries parts for it.'
The boys were disappointed. As Frank put the pedal back in his pocket he asked the proprietor
where parts for the Belgian bicycle could be purchased.
'It might be worth your while to check over in Bridgeport,' the man said. 'I think you'll find Traylor's handles them.'
'It's an odd coincidence,' Frank remarked, when the boys were back in the car. 'We've come across two Belgian bikes in two days.'
When they reached the Traylor store in Bridgeport, the young detectives learned they had just
missed a customer who had purchased a pedal for a Belgian bike.
'Who was he?' Frank inquired. 'I don't know.'
''What did he look like?' Joe asked. The proprietor's brow wrinkled. 'Sorry. I was too busy to pay much attention, so I can't tell you much. As far as I can remember, he was a tall boy, maybe about fourteen.' The three friends knew this vague description was almost useless. There
probably were hundreds of boys living in the surrounding area who fitted that description.
As the boys reached the street, Joe said determinedly, 'We're not giving up!'
'Hey!' Chet reminded his friends. 'It's almost time to pick up the girls.'
Within an hour the five young people were turning off the highway onto a side road paralleling Elekton's east fence. A little farther on Chet made a right turn and followed the dirt road that led to the rear entrance of the plant.
'Any luck sleuthing?' Pretty, brown-eyed Callie Shaw asked the Hardys.
'What makes you think we were sleuthing?'
'Oh, I can tell!' Callie said, her eyes twinkling. 'You two always have that detective gleam in your eyes when you're mixed up in a mystery!'
'They certainly have!' Iola agreed, laughing.
When they reached a grove bordering Willow River, which was to their left, Chet pulled over.
'I'll park here.'
The girls had decided they would like to see the changes which had been made in the old mill.
As the group approached Elekton's gatehouse, they were amazed at the transformation.
No longer did the mill look shabby and neglected. The three-story structure had been
completely repainted and the weeds and overgrowth of years cleared away. The grounds and
shrubbery of the whole area were neatly trimmed.
'Look!' said Frank. 'There's the mill wheel!'
As the Hardys and their friends watched the huge wheel turning, they felt for a moment that
they were living in olden days. Water which poured from a pond over a high stone dam on the
south side and
through an elevated millrace caused the wheel to revolve.
'Oh!' Callie exclaimed admiringly as she spotted a little bridge over the stream from the falls.
'It looks just like a painting!'
About three hundred yards from the north side of the mill was the closed rear gate to Elekton's ultramodern plant.
'Some contrast between the old and the new!' Joe remarked as they left the dirt road and walked up the front path to the gatehouse.
Suddenly the door opened and a dark-haired, muscular man in uniform came out to meet
them. 'What can I do for you?' he asked. 'I'm the gate guard here.'
'I'd like to apply for a summer job at Elekton,' Chet told him.
