Leah and the others took a stumbling step backwards as Gladstone advanced towards them, but there was nowhere to go. If they wanted to escape, they’d have to climb back up the pyramid.

‘Professor, don’t do this!’ Khalid pleaded, his eyes wide.

Gladstone shook his head. ‘I’m sorry, my boy, but you’ve left me no choice.’

‘We trusted you!’ Khalid said angrily, but Gladstone only shrugged.

‘Then none of you is as clever as I thought you were,’ he said, taking another step forward. Leah glanced nervously behind her. They were getting closer and closer to the edge of the pyramid. Time was running out!

‘When Amina tells the police about this—’ Mimi started, but the professor laughed cruelly.

‘Ha!’ he cried. ‘I hope she does report me, my dear girl! I’d love to see who the authorities would believe. Me, a harmless academic, or your aunt, a scandalous woman who has a reputation for being difficult?’ He shook his head dismissively.

Leah stared at Gladstone in dismay. The professor sounded like he’d thought all of this through. And maybe he was right. She’d seen how people had reacted to Amina. The scholars on the boat had dismissed her completely, and those women had been so rude. What if the police were the same? They had to get back to camp so they could tell Amina everything Gladstone had said. But how? There was nowhere for them to go.

Suddenly, Khalid nudged Leah in the ribs. He tipped his head to the side, towards the pyramid wall. Leah squinted, but she couldn’t see anything apart from the craggy surface of the pyramid’s sloped side. Wait . . . was that something moving there? She leaned forward. Yes! It was . . . a cat! In the dim light, she could just make out the small form of Bast slinking down the uneven path. The darkness, combined with the colouring of her fur, meant that she was almost invisible.

‘Enough of this!’ Gladstone suddenly roared, his face coming alive with anger. ‘Give me that amulet!’

At that exact moment, Bast reached the professor’s legs. She began to twine around them, her tail flicking up and down in a way that reminded Leah of the snakes from the pyramid.

Gladstone leapt in the air. ‘What—’ He hadn’t seen the cat and now he tipped his chin down. Everything seemed to slow down as Leah’s eyes darted between Bast and the professor. This was their chance. They wouldn’t catch him off-guard again.

‘SNAKE!’ she yelled, pointing towards the professor’s legs.

Just as she’d hoped, the professor yelped, dancing from foot to foot in panic as Bast’s tail curled up his shins. ‘Get it away from me!’ he shrieked. At the same time, William suddenly launched himself forward, the pain of his ankle forgotten, as he aimed towards the professor’s knees. The two of them landed in a heap on the path. The professor gave a cry and gripped William’s shoulders, trying to push him off, but William was too strong. Behind them, the bodyguards lurched forward, as if they, too, might try and pry William and Gladstone apart, but as they rolled back and forth, Leah saw they were perilously close to the edge of the pyramid. No one could get close without risking losing their own footing. She gasped, her hands covering her mouth.

‘William!’ she cried. ‘Watch out!’

But it was too late. William and the professor rolled right to the edge . . . and then off it.