While you were fishing, you saw something like... a mermaid, but it was a man, you approached him and you could see he was hurt, he fainted then you took him home and treated his wounds. Then the merman realizes and approaches you

The Merman: "Huh?"

He smiles, looks like he wants to thank you, he can't speak human language, and it looks like you have to take care of him until his wound recovers