Craning to see his son, Langdon smiled. ‘Something to do with wanting to say goodbye to his newfound friends in person. That was it, wasn’t it, Caleb?’

Xander turned to me and muttered, ‘That’s touching,’ as Amelia, apparently intent on changing the conversation, said, ‘When I was small I had an ammonite collection. I used to go looking for them on the beach in Lyme Regis with my uncle. Fossicking, it’s called.’

Caleb has small ears. The one nearest me was definitely turning red, as was the side of his neck. I’d not seen where Amelia was going with her strange fossil anecdote, but perhaps he had. She brought it round to his impending work experience, with, ‘What I mean is that rocks can be very interesting: I hope you have as good a time down the mine as I did on the beach.’

‘Thanks,’ he grunted.

Amelia generally talks with the certainty of a newscaster, but now she was almost stuttering. ‘I’d certainly b-b-be interested in seeing a mine myself, one day.’

‘I’m sure Caleb will report back,’ said Langdon slyly. ‘No doubt you’ve got each other’s numbers.’

It seemed Amelia might nod her head off in front of me. My mouth tasted stale all of a sudden. I’d brought my camera with me and raised it to my eye now, wanting to distract myself. On the kerb opposite a man was selling long loaves of French bread from a plastic crate between his knees. He had this slick way of flipping the sticks out of the crate and into a long thin plastic bag in one movement: it was mesmerising to watch. We worked our way into a district full of taller buildings, and within a few minutes pulled up in front of an office block. It had mirrored windows and sat behind railings. To one side of the entrance stood an SUV identical to the one we were sitting in. ‘There’s your ride, boy. Better get going, if you can tear yourself away,’ said Langdon. In order for Caleb to climb out of the SUV Amelia had to scoot her seat forward and shift sideways so he could reach the door. In the end she stepped down to the tarmac with him and waited there while he retrieved his luggage, a sort of camouflage-patterned military kitbag. Ridiculous. Willing him to be gone, I was surprised when he reached back into the truck and thrust his hand at Xander and me in turn.

‘Thanks,’ he said, shaking mine.

I gave him a whatever shrug.

‘And … sorry.’ Saying the word seemed trickier for him than coughing up a lump of concrete would have been.

‘Sure.’

‘I mean it. I apologise, and I’m grateful,’ he said more emphatically, before turning away.