It should not have made the difference that it did, and yet it did. Their three visitors stayed for two nights, going swimming with the ’Ktik during the second day. Byr met Aist again that night. The following day the visitors left, climbing into the module which the Unacceptable Behaviour sent down for them. The ship was heading off to loop round a proto-nova a few thousand years distant. It would be back in two weeks to drop off any further supplies they might need. Dajeil’s baby would be born a couple of weeks after that. The next ship due to visit would be another year away, when they might have doubled the human population of the planet. They stood together on the beach. Dajeil held Byr’s hand as the module climbed into the slate-coloured clouds.

Later that evening Byr found Dajeil watching the recording in the tower’s top room, where the screens were. Tears ran down her face.

There were no monitor systems on the tower itself. It must have been one of the independent camera drones. This one must have landed on the tower that night, found two large mammals there, and started recording.

Dajeil turned to look at Byr, her face streaked with the tears. Byr felt a sudden welling of anger. On the screen, she watched the two people embracing, caressing on the tower’s moonlit roof, and heard the soft gasps and whisperings.

‘Yes,’ Byr said, smiling ironically as she pulled off the wet suit. ‘Old Aist, eh? Quite a lass. You shouldn’t cry, you know. Upsets the body’s fluid balance for baby.’

Dajeil threw a glass at her. It smashed behind Byr on the winding stair. A little servitor drone scurried past Byr’s feet and windmilled down the carpeted steps on its little limbs, to start cleaning up the mess. Byr looked into her lover’s face. Dajeil’s swollen breasts rose and fell within her shirt and her face was flushed. Byr continued to peel off bits of the wet suit.

‘It was a bit of light relief, for grief’s sake,’ she said, keeping her voice even. ‘Just a friendly fuck. A loose end sort of thing. It--’

‘How could you do this to us?’ Dajeil screamed.

‘Do what?’ Byr protested, still trying to keep her voice from rising. ‘What have I done?’

‘Screwing my best friend, here! Now! After everything!’

Byr kept calm. ‘Does it count as screwing, technically, when neither of you has a penis?’ She assumed a pained, puzzled expression.

‘You shit! Don’t laugh about it!’ Dajeil screamed. Her voice was hoarse, unlike anything Byr had heard from her before. ‘Don’t you fucking laugh about it!’ Dajeil was suddenly up out of her seat and dashing towards her, arms raised.

Byr caught her wrists.