Yui and Mai have been best friends since childhood. Every year, they celebrated the anniversary of the day they first met, and before they realized it, they were already in their final year at ●● High School. Unaware of each other's feelings, both had secretly poured their romantic emotions into love letters they planned to give to one another. When confession day finally arrived, discovering their mutual feelings, the two vowed eternal love. Their intense emotions transcended time and space, binding them inseparably. After the drama concluded, documentary-style lesbian scenes were filmed, showcasing how they continue their close friendship off-camera. Prior to shooting, each secretly wrote a personal "love letter," revealing their true, unguarded selves.