Heaps of Pearl by Seanan McGuire
"Someone you know?" I murmured.
"You could say that," she said. "Excuse me." She pulled her hand away from my arm and stepped, quick-footed, across the ballroom. I pursued, not fast enough to be indecorous, but enough to keep her in sight, and hopefully, to hear whatever followed.
As we grew closer, the red-faced man's words became clear. "—found, then I shall take this as a declaration of war against the Undersea. Do you understand that, Gilad? Produce my daughter, or prepare yourself for what follows."
"I'm right here, Father," said Dianda, stepping up to the red-faced man and taking his arm firmly in both hands. "See?"
He turned to her, mouth agape. "Dianda! Where have you been?"
"The man asks an excellent question," said Simon, appearing at my side as if he had finally mastered the Tuatha art of teleportation. "Where have you been?"
My tongue had temporarily deserted me. I gestured, mutely, to Dianda and her father. Duke Morcan of Saltmist.
"I was having a more substantial meal with a friend," said Dianda. "You said I should be finding allies in the Midlands. Well, I found one. He gave me cake." She flashed a quick, almost regal smile in my direction. I did not return it. How could I? I couldn't move.
"You should have told me," said Duke Morcan.
"But I didn't, and now I'm here, so no harm's been done."
Duke Morcan looked unconvinced. Like his daughter, he looked almost like one of the Daoine Sidhe; in his case, his ears and neck were exposed. The points of them were slightly too sheared-off, and there were lines in the flesh below his jaw that I took for closed gills. Dianda must have chosen her hairstyle in part to conceal those obvious signs of what she was, and I couldn't decide whether to be impressed by her cleverness or offended that she had deceived me.
Then you have seen mermaids, murmured her voice in my memory.
"Patrick? Are you listening to me?" Simon prodded me in the shoulder. "Where have you been?"
"Meeting a mermaid," I said. "And she didn't even hit me with a chair."
Simon squawked protests at me, demanding details, but I wasn't listening. My eyes were on Dianda as her father led her to the head of the room. I joined in the applause when she was announced as the new Duchess of Saltmist. I didn't hear a word they said after that. I was too busy listening to the echoes of her laughter, in the shipwreck she had so quickly made of my heart.
Seanan McGuire, Heaps of Pearl