See you later, Mermaid

Kazushi Kimijima, while traveling alone, meets Tatsumi Higaki by the sea and discovers they are both patrons of the same inn. Inviting Tatsumi for an evening drink, Kazushi pieces together why, little by little, his new acquaintance is so apprehensive... What will he do when Tatsumi unveils his deepest secret and with it, his deepest fear?