Yokodera Youto is always thinking about his carnal desires, but no one acknowledges him as a pervert. He learns about a cat statue that supposedly grants wishes. The boy goes to pray that he will be able to express his lustful thoughts whenever and wherever he wants. At the statue, Youto encounters Tsutsukakushi Tsukiko, a girl from his high school with her own wish—that she would not display her real intentions so readily.

As Yōto takes Tsukiko to an animal café to discuss their next move, they coincidentally discover that Azusa is working part-time as a maid. They intend to approach Azusa following her shift, but are forced to flee when they are reprimanded by a janitor for taking shelter from the rain near a love hotel. However, they soon find her working at yet another part-time job, later discovering she lives alone in an apartment. After Yōto confronts Azusa about this, he asks her on a date to get her away from work, with Tsukiko deciding to follow them. However, Azusa is less than happy with Yōto’s choices for date venues, so Tsukiko steps in and they instead her to an arcade, where Tsukiko wins Azusa a stuffed turtle. Despite managing to get along, Azusa gets a bit upset when Yōto brings up the topic of friends. Just then, the track and field president and Tsukiko’s older sister, Tsukushi, shows up, forcing Yōto and Tsukiko to flee when she enquires about their ‘date’. When they return to the arcade, they discover Azusa being tormented by some girls from her old school, leaving her cold towards Yōto and Tsukiko, believing them to have strung her along.

After failing to get Azusa to talk to him, Yōto confronts her former classmates over what happened. They had apparently teased her at her old school due to skipping it a lot, telling her their class was going on a field trip somewhere when they were actually going elsewhere, which led to her becoming distrustful of others. After hearing this, Yōto takes Azusa to the stony cat, telling her about his facade that she acquired and stating his sincere wish to become her true friend. After coming to understand his feelings, Azusa wishes on the stony cat, returning her facade to Yōto. Meanwhile, Tsukiko remembers a time when Yōto once gave her advice on how to get along with children. After showing Yōto a story presentation based on this encounter, which doesn’t ring a bell for him, Tsukiko explains that she doesn’t get along with Tsukushi and she believes she hates her.

Tsukiko explains that she felt her clingy behaviour drove Tsukushi away from her, which led to her making the wish on the stony cat. As Yōto tries to ask Tsukushi about this, it is revealed that she was the one who made the stony cat as a way of apology to Tsukiko following an argument. The next day, Tsukiko asks Yōto to help her shop for costumes for her performances with the children. Later that night, Yōto encounters Tsukushi, who states that she wants to get rid of her sisterly bonds with Tsukiko and doesn't believe her lack of expressions to be related to the stony cat. Afterwards, Tsukiko expresses her concerns that if she were to get her expressions back, there would be nothing connecting her to Yōto. Earnestly wanting to help Tsukiko, Yōto gets Azusa's help and calls out Tsukushi to the stony cat. There he asks the stony cat to take away his urge to run away in exchange for his underwear. He announces that he loves Tsukiko as his little sister leading to Tsukushi to reveal that she does love Tsukiko, albeit in a romantic way and that she wants to cut off their sisterly bonds so that they could get marry in Massachusetts, a dream that is quickly shot down by Tsukiko. Tsukushi then calls out to the stony cat, who returns the meat bun containing Tsukiko's expressions, but Tsukiko decides to give it to Tsukushi instead. Some time afterwards, as the stony cat's power has assumedly disappeared and Tsukiko has been rather cold towards him, Yōto is shocked to discover his house has suddenly disappeared.

As Yōto asks for Tsukiko's help in determining the whereabouts of his house, Azusa becomes frustrated, having gone with Morii and Moyama to Okinawa expecting Yōto to show up as well, when he had just arranged it so they can make up. With rain settling in, Tsukiko invites Yōto to stay the night, which leads to various awkward situations when Tsukushi comes home as he comes out of the bath. Whilst attempting to break free from a sleeping Tsukushi's grasp later that night, Yōto hears her sleeptalking about her fears of Tsukiko leaving her. Meanwhile, in Okinawa, Morii suddenly collapses with a slight fever, but is helped by Azusa and Moyama. After Morii recovers, she and Azusa apologize to each other and reaffirm their friendship. Back at the Tsutsukakushi household, as Yōto hides inside the building to avoid the wrath of Tsukushi after walking in on Tsukiko naked, he discovers, amongst most of his house's belongings, the stony cat.

On the last day of summer, Tsukiko found Yōto in there storage room sleeping. Yōto explain that storage room has everything found in his house and the only theory he has is that the strange cat-statue has to do something with it. On the next day Yōto asked Tsukushi about the cat-statue and it turned out that is is a god which their family worshiped and she also asked Yōto a favor to trick his "twin brother" to somewhere alone and kill him but Yōto said that Tsukiko would be sad so she must first find a way to discourage Tsukiko from liking Yōto's "twin brother". later that nigh while he was in his "house" Azusa called him and asked why didn't he called her and if he want to see Azusa in her swimsuit. While talking on the phone he said that he wanted to see Azusa in her suimsiut then out of nowhere she suddenly fell on top of Yōto. Later that evening after dinner Yōto explain to Tsukiko what happened and told her that the cat-god must have been the cause, Tsukiko felt guilty and apologized and said that she only wished to be together with Yōto. near bed time while Yōto was thinking about something, Tsukushi barged in and trying to seduce Yōto in attempt to discourage Tsukiko. in their conversation Yōto found out that Tsukushi only did it for Tsukiko because she was afraid that Yōto would take her away and leave her. In the heat of conversation she wished that the world fall into ruins. in an instant the cat-god grant her wish and the whole building came crushing down leaving a scene of devastation

As the typhoon continues to grow worse, the house begins to flood and the discovery of a hidden room freaks out Tsukiko. Yoto starts to notice some weird anomalies suggesting this storm might not be caused by just Mother Nature.

It was a wonderful morning the Yokodera and Tsukiko went to school together while discussing their plans later than day for the school festival then suddenly a pink-haired little girl showed up, then it accrued that she was Ponta's little sister named Emi. Emi kept calling Yokodera onii-san (big brother) and seemed very friendly with him but at the same time Tsukiko seemed not to like Emi very much and had a feeling that she is a evil-plotted person,then she said that Yokodera should take Emi for a tour of their school and would wait for him afterward for their practices.Emi learned that Yokodera is a well-known "pervert" is his school so Emi took out a Cat-statue-figure like the one found in the storehouse of Tsukiko's house and wished Yokodera would be a "cool" guy in his school.　Weird thing happened, the school suddenly having Roman ancient architecture like the Colloseum, every girls in the school called Yokodera as prince and the school swimsuit as the uniform in the school. Tsukiko showed disbelieve when Yokodera told her it is not his doings. Tsukushi suggested to go to Yokodera's house after asked Yokodera to send his 'yonger brother' a message.　After seeing a photo taken out by Tsukushi when she is visiting Yokodera, he found something weird about the girl, Emi, because the name 'Emi' so happened to be Ponta's rabbit's name.

On his way to school while still being bothered by Emi's wishes and existence and Tsukiko's cold behavior towards him, Yōto is informed by Ponta about his rabbit gone missing whilst realizing that Emi's wish of being Ponta's younger sister has been cancelled. At school, Yōto makes up with Azusa as the latter agrees on helping him locate Ponta's missing rabbit. Emi later cancels a wish of having the girls in their school wear swimsuits after she had her swimming match with Tsukiko as she recalls to Yōto of the person she really got along with. Ponta later reclaims his lost rabbit thanks to Azusa's efforts whilst remembering of Emi and Yōto's close relationship, much to Yōto's bewilderment. The following morning, Emi cancels all her wishes after badmouthing Yōto but later discovers that not all Emi's wishes were lifted; their still-Italic school, as Tsukushi reveals to Yōto that she is transferring to Italy. Suddenly, Yōto founds Emi by the top of their school's tower and prompts to have a talk with the latter to appease their situation. Meanwhile, Yōto and Emi discovers that Azusa is being possessed by the cat god after Azusa's wish of becoming a new person. The cat god explains that it was all Yōto's wish of turning their school Italy from the start and that Emi is only a minor tool for its fulfillment. Wishing that the cat god should disappear along with Azusa's body and prompting Yōto to cancel his wishes in exchange for Emi's existence, Yōto forcibly kisses Azusa, removing her from the cat god's control whilst cancelling Yōto's wish yet sparing Emi in the end.

As Yōto's cancellation of his wish only took a partial effect at his school along with the cat statue's sudden disappearance, Azusa became madly in love with Yōto, much to Mai's nuisance. Checking up on Tsukushi, Tsukushi prompts both Yōto and Mai to make amends before she leaves for Italy but fails. Later, Yōto founds Tsukiko lamenting in his room as she hides inside Yōto's dakimakura but was later found out by Yōto himself. Tsukiko later leaves Yōto's room after knowing that Yōto has met Emi long before her despite her earlier claims that she was the one who knew Yōto the longest. Yōto then found passport tickets to Rome and a letter, sent by her grandparents, both belonging to Tsukiko. Meanwhile, as Yōto takes Emi for a stroll, Emi notices that something's troubling Yōto and tells him to sort it out. At the Tsutsukakushi residence, as Yōto, who disguises himself as his "evil twin", and Tsukushi converse of the latter's deceased parents and disapproval of going to Italy to live with their grandparents, Tsukushi intended to look for concrete evidence of her late mother and them living together through old photos, but comes out empty-handed. Tsukushi and Tsukiko then claim that they'd met Yōto in the past and then search for evidences regarding it, but only finding an unfocused picture of the sibling's late mother. While tagging along with Tsukiko, Azusa came to intervene and had a pep talk with Yōto. Afterwards, Tsukiko expresses her jealousy towards Azusa as she criticizes herself to Yōto. Claiming that meeting Yōto the longest would give her the advantage, Tsukiko wishes to see the past herself, followed by Yōto. Suddenly, a rabbit, possessed by the cat god grants their wish.

Tsukiko, who along with Yōto, has been brought back ten years in the past by the cat god. As they head to the Tsutsukakushi mansion, along the way they met the younger Ponta, Mai, Azusa, and eventually Yōto, much to Tsukiko's amazement. Shortly thereafter, they meet Tsukiko's mother, Tsukasa, who is brash yet somehow soft towards the younger Yōto, who at the same time badmouths him. Through the younger Yōto, Yōto and Tsukiko were invited for dinner at Tsukasa's mansion, which is at slight disarray. Here, Yōto and Tsukiko discover that Tsukasa's currently living alone and the younger Yōto constantly visiting her to keep Tsukasa company, much to the shock of Yōto and Tsukiko. Meanwhile, Yōto claims that he hasn't remember anything about interacting with Tsukasa, and later, learns that her daughters are currently living at Italy after the death of Tsukasa's husband. The following morning, Yōto stumbles on a young Tsukiko and later Tsukushi, who is deeply hurt of their mother's action of abandoning them. Tsukasa arrives, causing Tsukushi to harshly run off as Tsukiko then reprimands Tsukasa for being a horrible mother. Back in the mansion, a drunk Tsukasa dresses the younger Yōto with girl clothes as a drunk Tsukiko lies atop Yōto. Some time later, Tsukiko founds Tsukasa sewing clothes for her daughters. Tsukasa laments as the results of her inability to take care of her daughters has led her to her dwindling state as she ultimately passes out.

While a sick Tsukasa is being treated by the younger Yōto, the young Tsukushi, along with Tsukiko, agrees to visit their mother once again after Yōto persuades them. At the mansion, the young Tsukushi and Tsukiko wear the clothes their mother made by hand. Knowing that their mother loved them, the young Tsukushi laments over wanting to have memories with her mother. The younger Yōto reprimands Tsukushi, but nonetheless, gives her his precious memories with Tsukasa for their sake by wishing to the cat god, resulting in the current Yōto forgetting all about meeting the Tsutsukakushis and Emi in the past. Meanwhile, Yōto and Tsukiko return to the present. After heading back to the mansion, Tsukushi decides on not going to Italy and afterwards, Yōto and Tsukiko share a kiss. Days later, Yōto, along with Tsukiko, Tsukushi, Azusa, Emi, and Mai have fun at an amusement park.