The tide had never once come to the door of the lighthouse, and on the morning of Ysolde's twentieth birthday it came in and knocked.

She opened it in her nightdress, because that is what you do when the sea knocks. On the step stood a man made of the grey hour before dawn, holding a lantern that burned with green fire, and he said her name as if he had been practising it for a hundred years.

“You are late,” said Ysolde, which surprised them both. She had meant to say something braver. The man of the grey hour looked down at his lantern, and the green flame bowed, and for the first time in a hundred years he laughed.

Behind him the water was standing up. Not a wave: a wall, patient as a courtier, salt running off it in ribbons, and in it, turning slowly, the lights of every ship the town had ever lost.