Koikimo

On a rainy day, the elite salaryman Amakusa Ryo almost falls down some stairs when he is saved by an ordinary high school girl named Arima Ichika. Ryo was dizzy from not eating breakfast, which worries Ichika and she offers him her lunch then runs off. Later when Ryo gets home, Ichika is in his living room and he finds out that she is actually his sister Rio's classmate. Ryo wants to thank Ichika for saving his life and offers to kiss her...

Ryo gets home and he finds Ichika there wearing an apron. Ryo thinks he's daydreaming for a moment, but then he finds out Rio invited her as well as their other classmates, Satsuki and Ruri over. Satsuki and Ruri fall head over heels for Ryo. Meanwhile, Ryo's old friend, the photographer Masuda, hears rumors that Ryo had laid his hands on a high school girl and he tries to get to the bottom of this.

Ichika ends up slamming a volleyball into the face of her classmate, Tamaru Kai during gym class. She later goes to apologize to him when he's reading a book, but she realizes the book is connected to the anime that she loves, and Kai promises to lend her the series. That night Ryo meets up with Ichika at a convenience store so he can walk her home, and Kai also happens to be there. Ryo finds out that Kai is letting Ichika borrow some books. Kai tells Ichika that he'll see her tomorrow at school, but then Ryo calls him over.

Ichika and her friends talk about romance in class as the time for Christmas and their school trip draws near. Ichika is asked what kind of guy she likes and tries to describe someone exactly the opposite of Ryo. However, Satsuki then points out someone who actually fits that description. Meanwhile, one of Ryo's coworkers hears him talking to Ichika over the phone and hears that he addresses her as "Ichika-san" as well as him telling her that he loves her...

Ichika and Rio go to Okinawa for a school trip. Masuda ends up coming along with one of his seniors at work to be their camera guy on their trip. Rio had been sending pictures to Ryo from their trip, which ends up reminding Ryo of Kai and he gets worried. Meanwhile, Ryo ends up picking up an anime keychain that his coworker Matsushima Arie had dropped and she asks him to not let anyone at work know about her hobbies, and he has something nice to say in return...

Ryo's coworker Arie has been working as long as he has and is a secret anime nerd. They get a little closer after they talk about some anime. Arie starts to realize that she has feelings for Ryo and invites him out to dinner with some other coworkers. Meanwhile, Ryo drives Rio to Ichika's house after he finds out she's spending the night there. Ryo gives Ichika's mother various presents, making her ask him to come inside, but...