Okusama ga Seito Kaichou!

During the student council election speeches, Ui Wakana promises a liberalization of love, tossing condoms to everyone and wins by a landslide, to the dismay of her opponent Hayato Izumi, who becomes her vice president in the student council. After returning from cram school, Hayato discovers Ui in his apartment. She declares that she is his wife because their parents had drunkenly arranged for them to get married when they were 3 years old.

Hayato wakes up to find Ui in his bed. He discovers the "perfect student" she presents herself as is a facade, in fact she's rather lazy, useless at chores, and can't cook.

The head of the disciplinary committee, Rin Misumi, is upset that Ui's campaign has led to more public displays of affection. Hayato tries to show her that hand holding is no big deal by shaking hands with her but this embarrasses Rin extremely. That night, Ui suggests a hand-holding experiment and tries it out on Hayato, but it leads to a more erotic situation.

Rin continues to stop hand holding and public displays of affection by students, but Ui defends their actions. After class, Rin follows Ui and Hayato. When Hayato is alone, she confronts him and the two end up sheltering at a love hotel because of the rain. At that moment, Ui sees the two of them leaving the hotel together.

Ui becomes depressed after seeing Rin and Hayato come out of a love hotel. The council listens to a very similar case during their meeting, with Rin and Hayato vigorously defending the "it was a misunderstanding" side. When they learn in a follow-up email that the couple have made up with a kiss, Ui asks for the same from Hayato afterwards.

Ui and Hayato receive a surprise visit from Ui's mother Misato, who looks more like Ui's little sister. Misato visits Hayato's apartment for dinner, and then shares an awkward bath with him. Ui later gives Hayato a back massage which leads to tickling and foreplay until Misato interrupts.

Rin and Kei Misumi move in next door to Hayato, who tries to keep his cohabitation a secret. Rin visits Hayato frequently, causing him to try to hide Ui. But Ui gets revenge for his not paying attention to her. Rin finally finds Ui's underwear and lipstick, and Hayato has to claim they are his to cover Ui, leading to a rather embarrassing misunderstanding.

As Hayato prepares for a major exam, Rin and Kei notice his bags under his eyes and take him to the nurse's office. Hayato is surprised to learn that Rin told Kei about his alleged cross-dressing secret. As Hayato sleeps, Rin and Kei dress him like a girl and argue over who's panties he should wear.

Rin gives Hayato a gift bag with panties, while petite girls Sawatari and Karen watch them. Karen tells Ui that Rin is bribing Hayato, which leads Ui into thinking whether she should reveal her relationship secret to Karen and Ayane.

While waiting by the school entrance, Hayato sees Sawatari fall down while carrying a huge backpack, and brings her to the infirmary to rest. Sawatari suspects that Hayato and Ui's relationship is more than it appears, so she follows him home. Things quickly fall apart once she is invited inside.

Sawatari returns Hayato's panties and leaves a thank-you present for him. Ui, who has turned the legal age to marry, thinks the gift is for her and puts on the nightie. At first Hayato is shocked to see her in such daring clothes, but succumbs to her foreplay.

Ui and Hayato receives another surprise visit from Misato at their apartment. This time, Ui's father Ryouji comes along to see if Hayato is suitable to be Ui's husband.