Empire of Gold

Eddie took a closer look. The string had multiple knots of different types along its length. ‘So the map tells you what landmarks to look for, the colours of the strings show you the terrain . . . so the knots are, what? Directions? Distances?’

‘Both, in a way,’ said Nina.

‘The Incas had a system of sacred routes radiating outwards from Cuzco,’ Osterhagen explained. ‘They were called ceque pathways, and they connected all corners of the empire. Some were actual roads or paths, but most were just straight lines from one huaca to another. We knew that the pathways had ritual significance – the most important ones, the forty-one ceques around Cuzco, can be linked to the lunar calendar. But nobody has ever worked out how to connect all the others around the empire.’

‘Until now, at a guess,’ Eddie said, seeing that Nina was practically bouncing in her seat with excitement.

‘You got that right,’ she told him with a broad grin. ‘Leonard used the data he got by backtracking from Machu Picchu to Cuzco to figure out that the knots closest to the main cord give you directions, based on star charts – the Incas had a very advanced astronomical system.’

‘Not as good as the Egyptian one, though,’ Macy chipped in, defending the non-Cuban half of her heritage.

‘Maybe not, but still accurate enough to be usable for navigation. So that’s part of the key. And the other part is also on the khipu – the rest of the knots. The Inca numerical system was decimal, like ours, and on a khipu it worked like an abacus. The knots represent units, tens, hundreds and so on, depending on their position. If you know the system, you can tell what number’s recorded on a piece of string at a glance, or even by touch.’

‘Again, because I had reference points,’ said Osterhagen, ‘we were able to work out what the numbers meant. They are indeed distances. Nina calculated how they relate to huacas in the real world. In her head,’ he added, impressed.

‘So you know the total distance they travelled?’ asked Kit.

‘Something like seventeen hundred miles,’ Nina replied.

‘Jesus,’ said Eddie. ‘And you said it was a thousand miles in a straight line? Seven hundred miles is a hell of a detour.’

‘It’s because they were sticking to what they knew for most of it,’ Macy said. She opened up a large map of South America. ‘From Cuzco, they were pretty much heading northwest along the east side of the Andes. I guess they didn’t want to go into the jungle.’

‘But they had to eventually,’ added Nina. She pointed back at the section of the khipu where the coloured threads became predominantly green and blue. ‘We think the green ones represent jungle terrain. And the directions at the top of each string almost all indicate northeast. The blue ones, it seems likely that they mean to follow rivers.’

‘Makes sense,’ said Eddie. ‘Not a lot of other landmarks in the jungle.’

‘Especially if you’re used to living amongst mountains.’ She moved her finger back along the khipu. ‘So if we backtrack from Paititi, they covered long distances with comparatively few changes of direction . . . and then here’ – she indicated the point where the colour scheme reverted to the redder end of the spectrum – ‘is where they crossed from the Andes into the Amazon basin. But even up in the highlands, they were still heading mainly northeast . . . until here.’

Eddie examined the strings she was pointing out. The exact meaning of the knots at their tops were a mystery to him, but he immediately saw what she meant: those to the right of her finger were tied right over left, while on the other side they were fastened left over right. ‘So that’s where they changed direction,’ he deduced. ‘They stopped following the Andes and went out into the jungle.’

Nina nodded. ‘That’s the dogleg, where the extra seven hundred miles came from. And it’s something else too.’

He could tell from her struggle to contain another smile that it was something big. Which, considering what they were looking for, could only be one thing. ‘El Dorado?’

‘El Doraaaa-do!’ she sang, showing him a blow-up of the painted city, the Punchaco – and the final piece of statue – at its heart. Mac chuckled at her unrestrained enthusiasm. ‘The number of huaca markings on the map before you get there is exactly the same as the number of strings on the khipu up to the point where they turn northeast. They left Cuzco, headed along the Andes, thought they’d found a safe place to hide the empire’s greatest treasures . . . then had to move again to avoid the Spanish. But they left some of the treasure behind. And now . . . we can find it.’

Eddie gave her a genially mocking look. ‘What, you mean you haven’t already? I thought you were supposed to be good at this archaeology lark!’

She pouted. ‘Well, we have only just had breakfast. At least give us until lunchtime!’

It took rather longer than that, the process of calculating all the directions and distances represented by each thread of the khipu and then relating those to known huacas throughout Peru dragging on through the day. But Osterhagen’s knowledge of the country and its culture proved an enormous asset, even though he was at times on the verge of falling asleep at the table and had to be prodded awake by the two women. The Incas had illustrated on their map what were now known archaeological sites, and the German’s wealth of experience allowed the group to skip long sections of the trek, narrowing the possible location of the lost city each time.

While Nina, Osterhagen and Macy worked in the lounge, Eddie made a phone call from the bedroom. ‘Hi, Nan.’

‘Edward!’ came the delighted voice from across the Atlantic. ‘It’s so wonderful to hear from you. How are you, my little lambchop?’ His grandmother sounded somewhat stronger than the last time they had spoken, if still a little breathless.

‘I’m fine, Nan. I was going to ask you the same thing.’

‘Oh, I feel a lot better, thank you. I still have to wear this silly mask, but hopefully not for much longer – oh, excuse me.’ She stifled a yawn. ‘I’m a bit tired.’