Nombre original: 블루버스데이
Fecha de estreno: 23 de julio de 2021
Serie
Tiempo promedio: 24 minutos
Géneros: Sci-Fi & Fantasia, Drama, Misterio
Sinopsis: The series tells the story of Oh Ha-rin, who travels to the past through mysterious photos left by her first love, Ji Seo-jun. Since they were eight years old, they had been close friends, but he died by suicide on her birthday ten years ago.