His question remained unanswered for a long time. No one knew how they were to check Mr.Willliams' alibi. Even Fatty, who seemed to have the answers to everything, was at a loss. Everyone was completely silent. Even Buster did not sniff or bark. His doggy mind knew that the environment was serious. The silence was suddenly broken by Fatty's sharp voice.

"I'll go tonight! In disguise! Larry, you can come too. You are tall enough for an adult disguise"

"Thanks, Fatty. I'll be glad to come with you and wear a disguise, but ... where are we going and what are we doing tonight?" Larry asked.

"Just come to my shed at nine o' clock tonight. Then, I'll tell you what we are to do."

"It would be very thrilling to roam outside late at night" Bets sighed

"THIS IS SERIOUS BUSSINESS, BETS,not just roam -" Fatty started but was interrupted by Pip.

"We better leave now,Bets, is getting late" he said as he stood up and made his way to the door and Bets followed him.

"I bet we'll have to leave too" Larry said and got up."See you tonight, Fatty". The four left.

Later that day, Fatty wished his parents good night and went up to bed soon after dinner surprising his parents very much as Fatty usually stayed up late.

Fatty lay in bed waiting for the clock to strike nine. He felt excitement creeping over him. His mind was swimming in various thoughts about the mystery, the curious mark,the footprints in Brown Hill Mansion, the footprints on the pavement in Taplow. The mechanic boy's and cobbler's voice echoed in his ears. He heard the clock chiming. He leapt out of his bed and headed towards the door. He pulled on his dressing gown and Buster started whining softly.

"Sorry, Buster. Can't take you with me." he whispered.

He left the room and made his way to his shed. He saw Larry entering through the garden gate as he neared the shed. The two boys went into the shed. Fatty started opening his neatly kept draws at random and pulled out a pair of red eyebrows, his famous red wig and a red moustache. He threw them over to Larry and said, "Put them on, quick" still looking through his draws. Larry put them on and looked into the long mirror that hung on Fatty's wall.

"Don't mess with me" he said in a gruff voice. By then, Fatty had put on a curly black wig ang painted some freckles on his face. Then he put a cap on top of his wig and drew a thin black moustache above his upper lip. When both of them were fully disguised, Larry asked, "Now can you tell me what we are doing?"

"I thought you must've gussed by now! We are going to interview some nightwatchmen in Taplow, near the garage, to see if Williams had slipped out on the night of the robbery after 8:30, when the robbery must've been done. It was reported at

9 o'clock" Fatty said. They crept out of the shed noiselessly and Fatty locked it. They cycled off to Taplow through the bare roads and deserted streets. The boys' cheeks became pink as the cold breeze of the winter night blew past. When they reached Taplow, they stopped cycling as they were hot with layers of thick clothes and a long ride. They started to wheel their bicycles towards the towards the garage. They were glad to see that mostly all houses had night watchmen in that street. They walked to a house quite close to Mr.Williams'.

"Mind if we got some warmth in our fingers?" Fatty asked the watchman in a cheery voice.

"Not at all" he replied, streching both his arms towards the fire as if he were going to hug it.

"Thank you" Larry said and knelt down beside the fire.

"What are you people doing here at this time? Never seen you here before" the watchman said.

"Just came here on some work" Fatty replied. "Do many people roam about here late at night?"

"Not many, hardly any. Only that garage guy goes somewhere every night. I see him going just when I arrive. He's been doing this for about a week, running off to some head-going job. Never used to go like this before. Then, he returns late at night."

The conversation had gone exactly how they had wanted it to. They had got everything they needed. They caught each other's eyes and grinned at each other.

"The only other people are the other watchmen and rarely, some people like you" he said.

"Thank you" Fatty said as he got up. Larry got up too and brushed the knees of his trousers. They got onto their bicycles and rode away into the cold night.

"This proves that he's been outside on the night of the robbery" Larry told Fatty who had seen his watch and let out a low whistle. "I expected it to take much longer, it is hardly ten".

The journey continued in complete silence. When they reached Fatty's, both stripped off their disguises and Larry left after arranging to meet at his house the next morning. Fatty went up to bed and fell asleep in almost what seemed to be an instant. Larry went home and narrated what they did to a very excited Daisy. All five were asleep but their only thoughts were about the mystery. The next morning, all arrived much earlier than they were to, at Larry's house.

"Now, there is every possibility that Mr.Williams robbed the place, came back later and left that curious mark. Maybe, if we know what that strange mark is, we may know why Mr.Williams came there and probably confirm that he did the robbery" Fatty said.

"Cook said that Alice came back yesterday and discovered that the key was missing" Daisy said.