When Lala heard that all men are interested in boobs she started to make an invention that will make her boobs bigger. All of a sudden Rito flies out from a school window and crashes into the invention turning him into a girl.

Rito is always spending time with Lala, he barely talks to Mikan that much so she felt a little lonely and stormed out of the house alone, While Rito and Lala went looking for her, there are few flashbacks of Rito and Mikan in the past as Rito and Lala try to find Mikan.

Haruna wins a south island resort trip for ten females. She invites Lala and Mikan to the vacation. Rito, thanks to the mess that Lala left behind, activates one of Lala's inventions and gets stuck inside Maron's (Haruna's dog) body. Mistaking it as a bag that Lala left behind (the invention initially turns Maron into a bag), Mikan takes the bag with her, not knowing that she has also brought Rito along with them.

Rito and the others got stuck inside a RPG game made by Lala's sisters, Nana and Momo. In order to exit from the game, Rito and the others must defeat the great demon lord and rescue Lala. Rito, thinking Lala is behind the entire game, makes progress through the game. He does not realize that the real intent of the game is for Nana and Momo to analyze Rito and find out his true feelings. At the climax of the game, the demon lord teleports Rito to her castle and forces him to admit his feelings to Lala. As Rito cannot bring out a definite answer and Lala covered him up, the angry demon lord tries to defeat all of the characters by modifying the game to give her all the powerups and erase their data. Nana and Momo join in by summoning a giant talking Marron and Celine in her plant form and defeat the demon lord.

Rito finds Momo under the covers of his bed, before Nana, one of Lala's sisters, accuses him of sleeping with her. Nana questions Momo why all girls including Lala are attracted to Rito. After observing one whole day with Rito, Nana concludes that everyone is mistaken about Rito. Lala, Mikan, and Rito invite Nana and Momo to Hanami, but Momo turns them down, hoping to use this event to prove her statement about Rito. During the event, Momo summons an alien plant that releases pollen which will bring out everyone's true feelings. The pollen affects everyone except Lala and Rito. Nana does not feel convinced and forces the alien plant to release more pollen. The plant becomes possessed by its own pollen and captures Nana and Momo and later Lala. The plant drops Nana and Rito comes to the rescue, changing Nana's impression on Rito.

Yami and Yui confront with a senior; Yui subsequently loses her panties. She tries to search for her panties while hiding the 'secret' from everyone. Everyone questions about Yui's behavior. Later, an incident with Oshizu and a dog exposes her secret to Rito, but a teapot knocks him unconscious before he realizes what he saw, which he describes as "extraordinary". Mikan finds Peke taking snapshots of new clothing while shopping. Suddenly, a stranger steals her bag and runs. Mikan uses Peke's transformation to pursue the thief, who is actually an alien. When she finally confronts him in Yami's clothes, the alien initially mistakes her for Yami, but then notices her brown hair. He then tries to attack her, until Rito arrives at the scene and kicks him down to the ground. The thief tries to shoot down Mikan and Rito, but the real Yami arrives and defeats the thief. As Rito tries to explore Lala's cleaned-up bedroom, he accidentally activates one of Lala's invention, fusing his hand to Lala's tail. As Rito cannot get his hands off, he goes through a whole day of incidents, including a beating from Nana. During bedtime, Lala tells Rito she enjoyed being with Rito for a whole day. The effects wear off the next day, but Celine activates the invention, making her stuck to Rito's head.