The Stranger by the Beach (2020)

On an island off the coast of Okinawa, two young men meet on a beach: Shun Hashimoto, a gay novelist and Mio Chibana, a somber high school student. Day by day, the two of them grow closer, but then, suddenly, Mio decides to leave the island. They reunite three years later, and Mio says he is ready to be with Shun, but will Shun make the commitment?