‘These are ancient fortifications,’ Serif reported. ‘I saw in the notes that this area was the scene of a dramatic slaughter. These are earthen walls built by the Iceni against the Romans.’

‘Who?’ Greeneye had nothing but red rage in his face. Serif took a deep breath and kept running. ‘If you don’t learn the lessons of history…’ he whispered.

Bernice saw the stone features of Old Meg looming up on the hillock above her and doubled her speed. Her two pursuers would round the end of the channel down below in a minute or so, maybe more if they thought they were about to be fired upon.

Alexander popped up from behind the monument and called to her. ‘Turn to your right, don’t run ahead!’

She swerved and took a curving route round to the monument. She dived behind it, panting. ‘Wonderful diet. The Pursued By Aliens Plan. I can recommend it.’

‘How many did you get?’ asked Rocastle. There was no sign of the boys.

‘Two.’

‘One would have been better for a hostage.’

‘I’m terribly sorry. Did you manage to do anything with⁠ —’

‘Too dangerous. I think we managed to put those wonderful tools of yours to good use, though. Now, off to the flint pit with you two. I’ll wait here.’ He took his pistol back from Bernice with a wry little smile.

Alexander and Benny dashed down the hillside behind the monument. Ancient flint diggings provided useful cover there. The two of them leapt in, to find the boys lying there, an assortment of rocks and rough wooden stakes in their hands.

‘Oh, Bernice!’ said Anand. ‘Merryweather here has been fretting terribly about you.’

Merryweather glared at him.

‘Maybe we could have dinner when this is all over?’ Bernice winked at the embarrassed boy.

‘I, ah, beg your pardon?’ Merryweather squeaked. Alexander patted him on the head. ‘I do believe she’s teasing you.’

Greeneye and Serif ran out on to the light slope where the monument stood and looked around. ‘Where is she?’ Greeneye muttered, pulling both his swords from his harness.

They split up, fanning out in different directions. Rocastle peered out from behind Old Meg and winced. They were supposed to assume that the statue was the obvious cover and run straight for it.

Greeneye indeed was wandering towards him, but Serif was some distance away, slowly turning as if smelling the air.

Rocastle took a deep breath, poked his head out again and shouted. ‘Oh my God, they’re here!’

Greeneye spun. He ran at the monument.

And fell straight through the ground.

Before she’d left, Bernice had shown the boys how to use her excavation probe, a gravitic device that could, at its highest setting, create a large pit. Over that pit, they’d put a film of resin created by her ion bonder. Then they’d just thrown a light covering of the soil and grass from the pit back over it.