59 The Spire

59 The Spire As Peanut got her breath back she looked around. She had surfaced in a small round pool of purple water. Little-Bit and Rockwell were lying on the dirty concrete floor, breathing heavily. They had, like Peanut, lost their farmer disguises. Doodle, meanwhile, was sniffing at the bottom of a metallic door in the far corner, Peanut pulled herself out of the pool and shivered. Little- Bit looked at her. 'Poor 72,' she said sadly. 'It was the bravest robot I have ever met.'

It certainly was,' agreed Peanut. Another reason to rescue Dad and Mr M. We can't let 72's sacrifice be for nothing. Rockwell, any luck with that code?' 'I just almost drowned! Give me a chance!' He pulled the piece of slightly damp paper from his rucksack and started looking at it intently. In the corner opposite the door was a small desk with a computer terminal on it. Little-Bit walked over and started tapping away on the keyboard. 'I don't think they'll have Minecraft,' said Rockwell, smiling. 'Very funny,' said Little-Bit. 'OK, I've found a map of the building. Every floor and every cell is numbered and I would guess that this door leads into elevator shaft E3 which gives us direct access to the prison floors. All we need is Mr M's cell number. Peanut shook her head. Sometimes it was hard to believe that her sister was only five. ' So, Mr Codebreaker, we're all waiting for you. ' Well, it's got to be an anagram,' said Rockwell. 'I just can't work out why it's in blocks of five letters.

Little-Bit stood up from the chair by the computer and walked over. 'Don't you think that "Fathom" is a keyword?' she said to Rockwell. 'I told you, "fathom" means "work out". It's just telling us to work it out. 'Why would they do that? They don't actually want us to work it out, do they?' Rockwell looked at her. He realised that she was right. How annoying. 'OK, what do you mean by "keyword"?' 'Well, in my Junior Puzzler, there are often keywords that act as the cipher that cracks the code.' Of course!' said Rockwell. A cipher! A word that will, somehow, make sense of all the other letters. But how does "fathom" do that, clever clogs?' 'Well, it could do it in lots of different ways. Sometimes it is a literal clue, other times it's all to do with sequencing. 'What's sequencing?' asked Peanut. 'Duh. The order in which you read the letters.' Little-Bit took the piece of paper from Rockwell and stared at it for a full thirty seconds. 'Wait a minute... It couldn't be that simple, could it?' 'What?' asked Rockwell nervously. ' Yes! I knew it! It's a columnar transposition cipher!'

'It's a what?' said Rockwell. 'Now you're just making up words!' 'No, I'm not! It's a columnar transposition cipher!' She started to bounce with happiness. 'Oh no, please don't dance,' said Rockwell. 'Just explain what a communal transfiguring siren is. 'It'll be easier to show you. Peanut, can I borrow your pencil? Right. Let's start with our keyword, "Fathom"...' She wrote it down. FATHOM ' Now, if we were to assign each letter a number, from 1 to 6, depending on where it sits alphabetically, we would end up with this...' FATHOM 216354 'OK, Now let's add our mysterious blocks of letters. We'll put the first block of five, A, E, R, L and T in column "1"...'

FATHOM 216354 A E R L T 'Next, let's add the next block, M, K, O, E and N in column 2...' FATHOM 216354 MA KE OR EL NT

And so on...' FATHOM 216354 MARKMA KERFLO ORSIXC ELLTWE NTYTWO 'I still don't get it,' said Rockwell, puzzled. 'I do!' said Peanut. 'LB, you're a genius!' 'Can someone please explain?' said a forlorn Rockwell. 'It's so easy once you see it!' Peanut beamed. 'Just read across, line by line, left to right.' 'MARKMA, KERFLO, ORSIXC, ELLTWE, NTYTWO.' 'What does that mean'? Write it down. Come on, you're meant to be the smart one.' Rockwell took the pencil.