Yuri, a high school teacher, lives her busy days carrying a sacred "vow" in her heart: to fulfill the dream of the one she loved, Akira, who aspired to be a teacher but perished in the flames of war. One day, a temporary teacher named Ryo appears. Yuri finds herself constantly seeing traces of Akira in Ryo's casual gestures and words. Though confused by her wavering heart, she desperately tries to suppress her feelings for him, having resolved to love only Akira for the rest of her life.