The Mermaid and the Orca

After eavesdropping on her stepmother, the queen of a mermaid city, Y/n is troubled and decides to go out with friends to clear her head. While she is out, she comes across an orca trapped in netting. She feels there is something off with it, but can't place what. Later, when it is dark, she leaves the palace again and comes across a mysterious merman in a cave. Who is he? Will she be able to learn his secrets and uncover the treachery going on in the palace, or die trying? (Makoto Tachibana x Reader Fanfic)