Norfolk Crescent proved to be a quiet road in a rich suburb, with a large private square and a block of large flats, each of which changed hands for nothing less than a million pounds. The square was lushly green with shady trees that looked old and peaceful, and a nanny sat on a cast-iron bench reading the Harvard Business Review while her charge played on the grass with a set of lettered building blocks. The bird-song was loud, though not enough to drown out the noise of traffic to the south, and there was a scent of newly-mown grass in the air, though no sign of the grass cuttings. Squareknock leaned on the black-painted, man-high spiked railings that protected the square from intruders and gazed at the block of flats. They were outwardly modest and it was only when you started counting windows that you realised how big they must be. They were a dark-brown brick, the kind of colour that the architect had probably enthusiastically specified as chocolate and the builder had swapped out for mud.
"This is the place?" he said, though it was barely a question the way he said it. "Wealthy area, and these flats aren't cheap. I imagine you barely get two flats to a floor."
"Yer, this is the place," said Jason looking up at the flats. "I remember looking out of the bedroom window at this square and thinking it looked like a right nice place to lie down on a summer's day. It's all lit up at night, you know!"
"It sounds very nice," said Wilson, who despaired of Squareknock's refusal to move out of their Baker Street rooms and into somewhere a little larger. He knew that he'd miss Mrs. Bloodhound, but he also thought that if Holes were to stop shooting her he might stand a better chance of her seeing him as more than just a tenant. "It seems like a very quiet area, very respectable."
"Hah, you wouldn't want to live here, Wilson," said Squareknock still staring up at the windows of the flats. "There are some very unsavoury characters lurking in plain sight."
"Whatever do you mean?" Wilson looked around, but apart from Holes and Jason, all he could see still was the Nanny and the child. Holes pointed at the nanny.
"The hired help generally doesn't read the Harvard Business Review," he said ignoring the nanny's gimlet-eyed stare in his direction. "Especially not upside down, and if you look at the cover carefully you'll see that despite it being upside down the date is the right-way up and clearly visible in the wrong corner, the outside corner, of the magazine. The British Intelligence Services continue to amuse themselves by thinking that this kind of spycraft needs to be taught to new recruits, despite the laughable ease with which it can be detected. The blocks that the child is playing with are never out of order, as you would know if you'd been watching them. The child moves them around, but retains the relative order of them all, and they spell out the message to be communicated."
"They're spelling gibberish to me," said Wilson looking at the blocks. Now that Holes mentioned it, perhaps it was a little odd that the child hadn't thrown any of them off amongst the trees yet.
"Well yes," said Holes. "The message is encrypted using a simple Caesar cipher on an alphabet where all the vowels have been removed and the words first translated into Polish. There are a number of possibilities for the third, fourth and seventh words of the sentence, but there are hints in the images on the child's blanket. I am reasonably confident that I have correctly decoded the message, but there may be a nuance of detail that has escaped me."
"Bravo!" said Jason, actually applauding. The nanny gave him a filthy look and gathered up the blocks and child, dumping both unceremoniously into the pram.
"Well, thank-you," said Holes failing to look at all modest. "But that aside, which flat were you resident in one night? I think it likely to be number six or eight, but I confess I cannot presently find a reason to prefer one to the other."
"Eight," said Jason, his mouth hanging open in admiration. The nanny chose that moment to walk past, and neatly closed his mouth with a finger under his jaw.
"You might be on the iPlayer," she hissed at Holes, "but that doesn't give you free rein to ruin training exercises!"
"How did you know it was six or eight, Holes?" asked Wilson, who was in the habit of getting Holes to explain his deductions so that he could write up the story with as much detail as possible later on. "I would say it was impossible to know that."
"Ah, my dear chap," said Holes, radiating smugness. "It was really quite simple; I knew to begin with that Mr. Wilczys was hired to wet a bed, and a reasonably short time ago. As I shall demonstrate in a moment, Mr. Zippi does not reside at this address, and nor will he be known here, even when he is described. There are three floors on this side of the building that show signs of the owner's absence, but on only two of them are all the windows of one room flung wide open. I think it is likely that the room Mr. Wilczys stayed in needs airing after the owners returned home. I further suspect that since these flats are one above the other, the smell has permeated."
"Amazing," muttered Wilson, wishing he could take a moment to write Holes's words down.
"Amazing!" said Jason enthusiastically. "But Mr. Zippi does live there, he told me so himself. There wasn't anything illegal about my job!"
"On the contrary," said Holes with a toothy grin. "I would suggest that you don't tell the owner anything about your duties here when we talk to her.