Miyazawa Yukino is the most popular girl in school, but in real life she is a spoiled, lazy, stubborn, and unmanageable. She acts so perfect only to be admired, treated special, and pampered. Her only rival is Arima Souichirou, who is even more perfect than her. After a week of obsessing over this, she beats him in a test, but feels bad because she is a hypocrite. The next morning he confesses to her, but she refuses and regrets. That Sunday, Arima comes over to loan her a CD, and she accidentally shows him her true self.

At school Arima doesn't tell anyone about it, but starts to tease her about her true nature that he stumbled upon. He uses her secret as a weapon to make her do all of his work. He is also not who he looks like. One night he treats her to dinner. The next day Yukino falls asleep in the classroom and is found by Arima when he returns from kendo practice. Yukino struggles to understand why Arima is on her mind. She then realizes that she is in love with Arima. Everyone has started to notice the changes in her. Yukino has decided she will no longer be doing Arima's work and feels that Arima was just using her. Yukino tells Arima she is finished with him and runs out of the classroom, he chases after her. Arima explains that he just wanted to get to know her and he had no intention of ever telling her secret. The two then become friends. Arima starts to wonder why Yukino is always on his mind.

After Arima notices the differences between Yukino and his family he feels insecure and starts to avoid Yukino. Meanwhile, Yukino agonizes over why Arima doesn't want to be around her. Yukino realizes Arima is the only real friend she's ever had. She eventually confronts Arima about avoiding her. At first he's hesitant but in the end tells her. He is an adopted child, his real parents were blackmailers and thieves and they would abuse Arima. One day, they ran away because of a huge debt they had and left Arima alone. He was adopted by his father's older brother and they took good care of him. He felt that he could not open up to them properly because he was always trying hard to keep up a fake face to make sure no one judged him because of his parents. In the end, Yukino and Arima decide to let loose a little and slowly break away from the perfect images they had set up. Arima confesses to Yukino once again.

Yukino tries to think of multiple strategies of confessing to Arima, but things don't work out as the way she planned. She later realizes though that it's her stubbornness that is causing the strategies to fail. She then tries to make Arima nervous so she can confess to him. She realizes she is scared to tell Arima how she feels because of her fear of getting hurt by him. In the end, Yukino finally gets the courage to confess. But instead of saying it to Arima, she ends up holding his hand in a meeting. By the end of the day, they are boyfriend and girlfriend.

The school's Sports Fest has been taking up all of Yukino and Arima's time, making it so that they don't see each other at all for two days. Finally they pass each other while running to do some tasks for the festival. Being stressed out, Arima yells at some guys that were asking them for help. Then, Arima and Yukino go to the roof. It's awkward at first, but they then talk. After a comment that Yukino says, Arima makes a distracting comment of the weather and ends up kissing Yukino on the cheek. He then leaves to go back to work again. After a while, Yukino notices Asaba Hideaki. Since he's friends with Arima, Yukino tries to befriend him, but all Asaba does is be rude to her and walk away. This leads to a lot of fighting between the two of them. Arima also later asks Yukino on a date. While Yukino is walking in the hallways, she bumps into Asaba who tells her that he wants to use Arima as his partner to get girls and ends up making her feel bad. Arima, who knows what Asaba had done, later gets Asaba by the shirt and tells him that he's wrong. While Yukino is getting stood up by Arima, she bumps into Asaba who apologizes to her. He then tells her that he might even like her. Arima then comes sprinting to Yukino and explains to her that it was his mother. Asaba then grabs Arima and tells him to apologize but Yukino stops him. Asaba ends up joining their group.
Eyecatch (5): Thorns and then more thorns (千荊万棘, Senkeibankyoku)

Arima and Yukino go on dates like crazy and Yukino can't stop but staring at Arima. Arima then realizes he hasn't changed a bit as he has dated Yukino. One day Arima and Yukino are alone at school and Arima realizes that Yukino smiles like herself only when she's with him and they share their first kiss.

Arima's and Miyazawa's grades have dropped. The two of them have been spending time having fun rather than studying. The teachers call Arima and Miyazawa to the office and tell them they need to break up. Miyazawa stands up to the teachers and tells them that they will study, but love is more important than their grades. The teachers call Arima and Miyazawa's parents. In the end, the parents tell the teachers that they have no reason to tell Arima and Miyazawa to break up and trust their decision as they have always been responsible.

Arima invites Miyazawa over to his house on make-up exam day. They spend the day together and share their second kiss. Arima recalls how his life was before he met Miyazawa and how it changed after that.
Eyecatch (8): Serene and composed (安閑恬静, Ankantensei)

The girls in class 1A realize that maybe Miyazawa isn't really a model student after all. They start to ignore her. Miyazawa and Shibahime Tsubasa meet each other. She is jealous that Miyazawa has Arima's heart. Tsubasa is mean to Miyazawa but she is quickly caught by Arima who makes her apologize. Arima explains that he only sees Tsubasa as a little sister. She didn't mind until she found out he was with Miyazawa. This only further angers Tsubasa. Her friends come to talk to Miyazawa. The girls in the class wonder how much longer they have to ignore Miyazawa.

The girls are continuing to ignore Miyazawa. Arima wants to fix it, but Miyazawa refuses to let him help. She is still also feeling the wrath of Tsubasa. Tsubasa's friends have decided to make Yukino their friend. Miyazawa finally confronts Isawa Maho. The other girls in the class start to realize that they were being used by Maho who is incredibly jealous of Yukino. Tsubasa and Miyazawa have a confrontation after Tsubasa rips up a picture in Arima's wallet. They begin to have an understanding of each other. Everything starts to turn around for Miyazawa. People are accepting Miyazawa for who she actually is.

The end of the semester is finally here. Everyone is figuring out their summer plans. Arima won't be able to spend the summer with Miyazawa because he will be in a kendo tournament. It's the first time they've spent any time apart. Summer starts and Miyazawa is spending time with her new friends.
Eyecatch (11): Tender, protective feelings for women (憐香惜玉, Renkōsekigyoku)

Tsubasa insists on staying the night at Yukino's house, saying that with his engagement, her father no longer wants her, just like Arima. Yukino's family allows her to stay the night. Except for Tsubasa, they all play a round of UNO. That evening, Tsubasa's father and his fiancee arrive and explain the situation from his point of view. Yukino's mom tells Tsubasa's father that Tsubasa should stay the night at their house.

As she lies awake that night while spending the night at Yukino's, Tsubasa realizes she is being selfish, wanting her father all to herself and in the morning, she accepts the engagement. At a formal dinner, she meets her attractive future step brother, Kazuma, who is the same age as she is, but when he mistakes her for an elementary school student, she loses her temper. A few days later, they meet by accident and spend the afternoon together before going to Kazuma and his mother's apartment. At the end of the evening, she tells her father that she approves of the marriage, and they get married the next day.

A recap episode, summarizing the events of episodes 1 through 6.
Eyecatch (14): Turns and twists (紆余曲折, Uyokyokusetsu)

The first half is a recap episode, summarizing the events of episodes 7 through 13. The second half is about Asaba visiting Yukino at her home. Yukino finds out that Asaba lives alone due to an estrangement with his parents, particularly because of his inability to get along with his overly strict and formal father who resents his son's casual attitude.
Eyecatch (15): Difficulties of all shapes and sizes (多事多難, Tajitanan)

The Miyazawa family visits Miyako's father, who does not get along with his son-in-law, Hiroyuki. When Hiroyuki and Miyako walk through the neighborhood they recall their past in an extended flashback. As a child 'Hiro' was a little terror who terrorized Miyako and the other children with his rough play but mellows as he grows older. They are shown meeting occasionally in the following years as she follows him into the same middle school and high school, two years behind. It is Hiro's fondest desire to grow up and support his beloved elderly grandfather, who raised him alone after his parents died, in the same way that he supported him. When his grandfather dies before he can graduate high school it is Miyako who consoles him and asks if she could be the one he could live for instead. They marry young, right after her graduation, infuriating her father and causing the rivalry between the two of them.

After Arima finally returns triumphant from his training and kendo tournament, having won the national championship, Yukino finds it hard to deal with her increased affection for him. Her inability to express her feelings causes her to draw away from him, even running away from him when he confronts her about her distant attitude. Only when Arima loses his composure, corners her, and desperately declares that he will "never let her go" does she realize how much she has hurt him and is able to explain her feelings.

During a family get-together Arima's extended family verbally harasses him (as usual) but his foster father stands up for him and declares that no one should speak ill of his beloved son. In the second half of the episode Yukino and Arima are able to spend some time alone and bring their relationship to a higher level by having sex at Arima's home. This level of closeness causes Arima to have a nightmare about his past.

The new semester is underway. A mysterious transfer student, Tonami Takefumi, arrives, and preparations for the culture festival ignite Yukino's competitive spirit. Eyecatch: A fresh breeze, an old friend (清風故人, Seifūkojin)

Explanation and flashback about Sakura Tsubaki and Tonami's childhood bully-victim relationship and how drastically Tonami has changed since that time. Aya writes a screenplay in hopes that Miyazawa and the others will perform it for the cultural festival.

Aya successfully catches Miyazawa and Maho and tricks them into reading the screen play she wrote. Tsubaki and Tonami's relationship (or lack thereof) becomes extremely rocky while Tonami and Miyazawa's becomes friendlier. Arima becomes jealous, but Miyazawa dashes his insecurities aside for the moment.

Yukino and Maho assume lead parts in the play written by Aya Sawada. The girls form a drama club where Mr. Kawashima is a supervisor. Meanwhile, Arima becomes increasingly jealous and feels left out as Yukino spends a lot of time with her new friends. We also learn that Yukino's younger sister, Kano, is a big fan of Aya's stories.

After a couple of moments focusing on Miyazawa and Arima and then Tsubaki and Tonami, the focus stays on Miyazawa and the girls making the plans for the play.

Another recap episode, with some new material in the first half (Yukino dreams of flying while napping on the school roof).

This episode deviates from the main story, focusing on an anime original tangential story about the younger Miyazawa sisters, Kano in particular.

Yukino becomes very friendly with Takefumi and Arima becomes very jealous and possessive of Yukino showing his dark side to Takefumi. Asaba explains to Takefumi that Arima is actually obsessive over his relationship with Yukino and the only reason Arima lets him hang out with her because Arima knows that he'll never touch her. The second half shows Takefumi kissing Sakura and telling her that it was his first kiss and doesn't know why he did that. The series ends with Takefumi acknowledging his love towards Sakura and thinking how the future will be.