Sarah got to her feet. ‘I’ll make a fire from some twigs. Come on, Piet, you rinse off your knife and then we’ll put the blade into the flame to sterilise it. I’ll make the cuts, if Camilla and Hannah are too squeamish. I’m not a doctor’s daughter for nothing.’ She glanced over her shoulder at him. ‘Your knife is really sharp. If you don’t give it to me I’ll use my blunt old penknife, and I’ll be hacking great lumps out of our hands. Then your parents really will have something to say.’

Sarah cleared a space on the ground. She was about to search for kindling when Camilla appeared beside her with a handful of dry sticks. Hannah sat still, her expression solemn, and Camilla looked at her, silent but with eyebrows raised.

‘All right. I’ll do it. We’ll make our promise together.’ Hannah turned to address her brother. ‘And don’t even think of walking off into the long grass, Piet. Because you’re going to be our solemn witness. Give me your lighter.’

The twigs were soon crackling and a thin spiral of smoke rose from the heart of the woodpile. Sarah took Piet’s knife and held it over the flames. Then she stood up and held it out so that the blade glittered in the afternoon light.

‘I’ll go first.’

She saw Piet step forward in protest, but she deliberately ignored him as she made a quick incision on the mound at the base of her thumb.

‘Me now.’ Camilla did not flinch or avert her eyes as Sarah made the cut.

Hannah held out her hand, watching in silence as the scarlet drops welled in her palm.

‘Come over here, Piet, so we have a witness as we press our hands together and make the blood mingle,’ Sarah ordered. ‘By the way, Camilla’s blood isn’t blue. I hope that doesn’t come as a shock to anyone.’

‘We should make our promise now,’ Camilla said. ‘Something that always binds us, no matter how far we may travel from this day and place.’

‘I promise never to forget, always to stay true to our friendship. Always to be there for my sisters.’ Sarah’s eyes were very bright as she spoke and her face was grave.

Piet looked at Hannah and saw that there were tears in her eyes as she repeated the words. But Camilla was smiling as she pressed her palm into the hands of her friends and made her own promise.