The S.A is challenged to a pro-wrestling competition by the Student Council President, Hajime Kakei. Hikari and Kei accept the challenge, but run into trouble when the President decides to use underhanded tactics to beat them and Kei begins to worry about Hikari's safety without considering her feelings.

The greenhouse is vandalized and it seems that Hikari has a hunch on who may have commited the act. When she comes face to face with the suspect, he challenges the S.A - however, it must be Ryuu who completes the challenge. Old memories and feelings resurface for Ryuu while Hikari learns more about her friends.

After hearing about Hikari's date with Tadashi, Kei arrives from Shanghai with the intention of having her spend the day with him, as stipulated in a challenge he proposed to her earlier. However, he winds up getting a fever and Hikari takes care of him; as she does, Kei reflects on his feelings and relationship with her.

Akira's determination to protect her new friend, Yui, from Yahiro ends up pushing Yui away instead. Meanwhile, Yahiro's attempt to separate Akira from Yui comes with well-meaning intentions that Akira may never realize.

Hikari must go on a date with Kei on Sunday, as promised when he was recovering from a fever. However, their "date" is interrupted by Sakura Ushikubo, Kei's future fiancée, who takes Hikari away and befriends her. When she agrees to help Sakura find out more about Kei, Hikari begins to feel some unexplainable feelings regarding Kei.

The S.A. is invited to attend and plan a festival at Kokusen Academy by Sakura and Yahiro. Yahiro tries to tell Akira he cares about her, but decides against it when he realizes that she has feelings for Tadashi.

Upset that Tadashi does not seem to care about her, Akira goes to a matchmaking party with Sakura. When Tadashi apologizes to her, she becomes angry at herself for causing trouble. Yahiro helps Tadashi find a way to comfort her, and Tadashi decides to bring Akira to a viewpoint that they had been to when they were children.

Megumi asks Yahiro out, claiming she has a crush on him. Yahiro thinks there's more to it and agrees only if she's willing to play a "game" where she must make him say he liked the date before he believes she likes him. Meanwhile, Hikari catches a cold and the rest of the SA go to see her. When Hikari's parents leave her friends to take care of her, they find the feverish Hikari doing rather outrageous things.

Hikari, Kei, and Jun attend the opening of a new athletic park and run into Sakura. Jun avoids Sakura, who chases after him in hopes of discovering his true feelings for her, while Hikari and Kei must deal with the scores of girls that Jun's alter ego keeps attracting.

Hikari meets Aoi Ogata, a member of the Takishima Group who finds Kei important to him and is willing to do anything for Kei. When Aoi decides Kei is better off studying in London, Hikari must prove she's worthy of being Kei's rival. However, this meeting with Aoi causes Hikari to think about her true feelings for Kei.

Thanks to Aoi, the S.A class has been disbanded in order to force Kei to go to London. So that Hikari and his friends can remain together, Kei proposes a challenge to Hikari that if she wins, he will bring back the S.A. However, Hikari learns too late what Kei has done in order to bring back the S.A - he has already left for London for her sake.

Hikari and S.A head to London to find Kei and bring him back to Japan while Kei resigns himself to not seeing Hikari and his friends again. Everyone, including Yahiro and Sakura, overcome the obstacles standing in the way of reaching their friend. When Hikari meets with Kei at last, they finish the challenge he issued her and express their true feelings for one another.