‘Let me see if I understand you,’ La Dame said. ‘You, my friend, are going to attempt to solve a puzzle in the discomfort of a car with daylight dwindling and temperatures dropping; a puzzle that no one has solved in fifty years, even though they may have sat in comfortable rooms, in front of fires with entire libraries at their disposal? By the time you work out the frequency of the distribution of the letters in the cipher, we’ll all be dead.’
‘I know, so we have to work out the master word and fast.’
‘If only Arthur Conan Doyle were here, now there’s a genius,’ La Dame said. ‘Remember “The Adventure of the Dancing Men”, Rahn? A cipher of stickmen, each representing a letter of the alphabet – quite brilliant!’
Rahn looked up from his calculations, feeling querulous. ‘I still think Poe’s “The Gold-Bug” is by far the finest piece of fictional literature written on the subject.’
‘Totally improbable, dear Rahn.’ La Dame shook his head. ‘A gold bug that when suspended through a skull, points the way to treasure – ha ha!’
Rahn narrowed his eyes. ‘It was quite scientific and you obviously missed the point.’
Eva cut in, with a degree of impatience: ‘Are you going to argue all afternoon, or are you going to solve the cipher?’
‘All right,’ Rahn said. ‘Look . . . Fire may not be the word but I think it’s a clue. Let me think, there is a fire trial in all Mithraic initiations, a candidate dies to the earth and is born to the spirit, which is fire. This was illustrated in the mysteries by jumping over fire, or running through a fire-lit forest, or over hot coals . . . fire . . . fire . . . fire . . . death . . .’
‘But as I’ve already pointed out to you, the word fire was used by Saunière, and it didn’t work,’ La Dame repeated.
‘What about the Pentecostal fire?’ Eva offered.
‘Or the fire of Hell and eternal damnation?’ La Dame threw in.
‘Wait a minute – death, Hell or Purgatory! That makes sense. Purgatory,’ Rahn said, excited. He took the piece of paper with the list and a pencil he had in his pocket and began to write purgatoire, over and over without a break between words.
‘The one good part of that story about the bug, mademoiselle,’ La Dame said, ‘was the bit about the chemical preparations . . .’
Meanwhile, Rahn drew a Vigenère Square.
‘There are preparations,’ La Dame went on, ‘that are visible only when subjected to the action of fire. Remember, Rahn?’
‘What?’ Rahn said, annoyed at his interruption.
‘The gold bug, dear fellow – the man draws the shape of a gold bug that he finds on an old parchment and later, when the parchment is placed near a fire, it reveals an invisible writing. You see, mademoiselle, the writing only appeared when the parchment was heated—’
‘What did you say?’ Rahn paused to look at La Dame, utterly taken aback. ‘The gold bug!’
‘The invisible ink – remember?’ La Dame said.
Rahn blinked this in. ‘It couldn’t be that simple, surely? Give me your matches, La Dame!’
‘What for?’
‘I’m going to try it,’ Rahn said, taking the packet from his hands.
‘You’re not serious!’ La Dame laughed. ‘That was just a tale.’
‘It’s worth a shot.’
‘If you burn the parchment, that will be the end of it,’ Eva warned.
Rahn lit the match, held it a long way from the parchment and passed it back and forth, allowing the flame to warm it only slightly. Something miraculously appeared before their eyes – an alchemical transformation.
XOTDQTKWZIGSDGZPQUCAESJ
XSJWOFVLPSGGGGJAZ
MQTGYDCAXSXSDRZWZRLVQAFFPSDAPW
MITMZSKWZHRLUCEHAIIMZPVJSSI
POEKXSXDUGVVQXLKFSVLXSSWLI
PSIJUSIWXSMGUZVVQZRVQSJKQQYWDQYWL
Four letters turned red. ‘SROM–’ Rahn said. ‘I give up! What does that mean?’
La Dame shrugged, still puffing on his cigar, making the inside of the car feel like a chimney.
‘You can’t see the tree for the leaves, Rahn!’ Eva said. ‘Look at it!’
Rahn sat up. ‘You have to read it backwards – like the rebus, like in Journey to the Centre of the Earth . . . it’s MORS – in Latin, that means death! The master word is death and fire reveals it!’
La Dame nodded and slapped both hands together. ‘You see, I told you! It may be, dear Rahn, that you are not luminous, as Sherlock Holmes once said to Watson, but a conductor of light. Some people, without possessing genius, have a remarkable power of stimulating it.’
Rahn noted Eva’s smile and it did not amuse him. ‘Let’s not have a party, La Dame, until we know it works.’