Japan, 2022. Mai, 22, belongs to a moderately successful idol girl group called Happy Fanfare, aka HappiFan. Kei, also 22, is a university student working as a part-time camera operator. On the night he is assigned to film a HappiFan show, Kei recognizes Mai from his junior high school. This coincidental meeting thrills them both. Although Kei has no interest in "idols", he finds himself drawn to Mai as he films the group on stage. Soon the two fall in love. However, their romance has to be kept secret because Mai's contract stipulates a "No boys" clause. Still, Mai is happily in love and enjoys her profession. But that changes when a tabloid reports that a HappiFan member has a boyfriend. Nanaka, 19, has violated the "No boys" rule so she loses her regular role in the girl group. As she gives her fans a teary apology, Kei realises that his relationship with Mai could jeopardise her career, and so he retreats. Breaking up isn't easy for Mai but she tries to understand Kei's intention and to move on. Their love is rekindled when a fan goes berserk at a HappiFan event. Worried, Kei immediately drives to the venue when he hears the news. When Mai sees him, they take off in Kei's mini truck despite her manager's attempts to stop her. A few months later, Mai is no longer with HappiFan. Because of the "No boys" clause, the HappiFan management sues both her and Kei. Although both Mai and Kei engage lawyers, the court proceedings are overwhelming. As Mai lives with Kei in his apartment and works part-time, she has less contact with the HappiFan members. Then the management proposes a settlement deal to end the trial. Kei wishes to put the lawsuit behind them and start over together. Despite being still bothered by the implications of the "No boys" rule, Mai considers accepting the deal.
