By the time the family arrived at the beach, the sun was already setting. The eastern sky, a wonderful lilac, soothed them as the last shards of sunlight glittered on the sea. They could see the smallest sliver of moonlight beginning to show on the horizon... and then they saw her. The daughter ran forwards, splashing into the sea, young and carefree again. She dived forwards, and down, and down, and down until her lungs felt as if they were about to burst. On breaking the surface, her mother looked to her anxiously, "Emma? What did you see?"
"A Selkie, mum."
"A Selkie?" The girl nodded.
"She was beautiful, mum."
"I'm sure she was. Now," She waded in to reach her, "Come back and get dry. It's September, not July. Don't want you dying of hypothermia." Emma's father reached into his bag.
"Towel." He grumbled, having known his daughter would go in at some point. She always said she wouldn't, but she always did. The sea was irresistible to her.
They watched the moon rise in silence, as the sun set behind them and the lilac sky darkened to the familiar, deep blue they knew all too well. And far away, on the horizon, Emma saw a girl with wild green hair and a seal's tail wave, then dive away.