Heather mounted the ladder, with Peter close behind her. Albrecht held the light on them until they had gone. He said to Cynthia: ‘Now it is our turn.’

‘Give them time to wriggle through.’ She reached up and kissed him. ‘I am shameless, you know. Don’t worry. I rubbed my lipstick off as soon as we got inside the cave.’

He said: ‘I am glad you are shameless.’

With his arms around her, the light from the torch stabbed high over their heads towards the pointed arch of the ceiling. She shivered.

‘Doesn’t even this make you afraid of death?’ she asked. ‘The darkness under the earth?’

He said softly: ‘We must go, Cynthia.’