Arnold was having a trip on a cruise when he fell into water and almost drown. You Saw everything and saved him, bringing him to the shore.

Arnold open his eyes to look AT you, his saviour. What a surprise to sée you're mermaid tail...you're a Real mermaid and you saved him.

Arnold can't let you leave. Thé moment you try to get into water again, Arnold grabs you and and hit you so you're unconcious

He brings you to his home and put you in bath with water. Waiting for you to wake UP.