‘No, but I think I’ve made mistakes. The lesson they’ve taught me is actually my second rule: think before you dig. Before you put the tip of your trowel into the ground, ask yourself some very big questions. Am I the right person to make this discovery? Am I doing so for the right reasons? And most of all, do I have the ability to protect this discovery? If you can’t truthfully answer yes to all three, then you should hold off. Always remember that your actions will make you a part of history too – and you want it to look favourably upon you.’ She cast her gaze across her students, one by one. ‘What I’ve come to realise is that you need great wisdom to know if you should return an ancient wonder to the world. Even after everything I’ve experienced, I’m still not sure I have that wisdom.’ A pause, then, with dark humour: ‘And I’m damn sure none of you do.’

She knew that would not go down well. Most of the young men and women limited their affronted responses to facial expressions, unwilling to challenge a professor, but there were inevitably a few vocal objections. ‘I don’t think that’s fair,’ said Aiden. ‘You don’t know us.’

‘No,’ Nina replied, ‘not as individuals, but I’m forty-five, and by now I know people. You’re all, what? Eighteen, nineteen, twenty? That’s an age where in many ways I envy you – the whole world’s just opened up, and you can do anything. You can even bend down without your back hurting! Damn, I miss those days.’

The humour helped ease the tension. ‘But,’ she continued, ‘while you’ve got limitless energy and enthusiasm, you don’t have experience. And I can tell you, ironically enough from experience, that when you’re young, if someone tries to give you the benefit of their experience, you’re all like “yeah, whatever, grandma”. I was the same! And unfortunately, that got me into trouble – trouble that affected other people. If I’d realised what I was getting into, I would have done things differently. Or possibly not at all.’

‘But then everything you’ve discovered would have remained lost,’ said Cheng. ‘Our knowledge of ancient history would be incomplete. It would be wrong.’

‘It would, yes. But that goes back to my first rule – is that knowledge worth the lives lost to uncover it? All of you, take a look at each other.’ Nina waited for them to do so. ‘Now, if you thought you were on the verge of making an amazing discovery, but you knew that in doing so you’d be directly responsible for the deaths of some of your classmates . . . would you still do it?’

The question aroused discussion. Cheng was first to reply. ‘But that’s a flawed premise, Professor.’

She arched an eyebrow. ‘Is it now?’