When Yoshida, a normal salaryman, wakes up on a Sunday morning after a hard night at the bar, the last thing he expects to encounter is a new resident—an unfamiliar high school girl. Yoshida had been rejected the night before, despite finally finding the confidence to declare to his supervisor and lifelong crush, Airi Gotou. Yoshida returned home in a drunken haze after drowning his sorrows at a bar with his good buddy Hashimoto, only to stumble across Sayu Ogiwara, a runaway high schooler. She asked him to let her stay the night, and Yoshida agreed, his judgment muddled by booze. Yoshida now asks Sayu to explain what happened last night, despite the fact that he has his mind on straight.