Agata said, ‘If you’re so terrified of the old ways returning, why did you have a son at all? You got by without a brother. Why not wipe out your enemy completely and be done with it?’

‘Far better to keep them alive and weak,’ Cira replied, ‘than to turn against ourselves and reduce some women to playing the role of men.’

Agata arrived at the celebration later than she’d intended. It was easy enough to make allowances for the time it took to climb the rope ladders between the levels she frequented day to day, but when a journey took her up or down the old helical staircases she found it impossible not to dawdle. For six generations these elaborately carved grooves had been nothing more than peculiar decorations wrapping the walls of horizontal tunnels, but to traverse them now meant treading on stone that had last been used this way when Yalda was alive. If Agata spotted a blemish in the rock she had to stop and inspect it in the moss-light, hoping that someone who had walked on the home world – famous or obscure, she didn’t care – might have carved their name into these steps.

As she entered the observation chamber, she saw that at least six dozen people had shown up. The space couldn’t have held many more, but there were similar festivities taking place up and down the mountain’s rim. She squeezed her way through the crowd, moving aimlessly until someone called out to her.

‘Agata! Over here!’ It was Medoro’s sister, Serena. The whole family was gathered around a table by the edge of the dome.

Agata approached, trying not to be distracted by the view before she’d greeted everyone. The lighting in the chamber was subdued, but she still needed to stare out at the sky to convince herself that she really was seeing it – that her vision wasn’t being blocked by reflections from the interior. All the long, orderly star trails she’d grown up with, the great meridional arcs that together filled half the sky, had shrunk into the kind of tiny, random lines of colour that she’d only ever known before as the signature of the orthogonal cluster. This was the ancestors’ sky. In less than a chime, the mountain would be at rest with respect to the home world. Apart from the effect of the Peerless’s displacement on the arrangement of the nearest stars, and apart from the absence of Hurtlers and the sister-world-turned-sun, Gemma, this was the view that anyone on the night side of the planet would be seeing right now.

‘Cira didn’t come?’ Medoro asked, feigning puzzlement.

Agata wasn’t in the mood for jokes about her family – and apparently Medoro’s own relatives felt the same way: Gineto reached over and gave his nephew an admonitory thump on the arm, to Serena’s amusement. ‘Feel free to do that yourself whenever he annoys you,’ she suggested to Agata. ‘It’s the only way we manage to put up with him.’