It's Natsukomi
Yūto and Haruka attend the summer Comiket convention together, but since it is the first time for both of them, they underestimate the massive scale and hoards of people who attend. Mika, Hazuki, and Nanami tag along in disguise and help Haruka obtain a dōjinshi she wanted, and to get her out of trouble when people started taking pictures of her. Yūto and Haruka grow closer throughout the day, but after he leaves her at her house, Yūto is asked if he and Haruka were followed by anyone at the convention, but he says he did not see anyone like that. That night, a frantic Haruka unexpectedly shows up at Yūto's house.
Aired 15/08/2008EP 6 - It's Natsukomi
Haruka Nogizaka's Secret
The story centers around Yuuto Ayase and his classmate Haruka Nogizaka. While Yuuto is rather ordinary, Haruka is very attractive, intelligent and rich. Due to this, she is the school's most unattainable girl and is so idolized that her classmates give her the French nicknames "Nuit Étoile" (The Silver Star of the Night) and "Lumière du Clavier" (The Shining Princess on the Piano). One day, when Yuuto goes to the school library to return a book, he stumbles across Haruka and her darkest secret—she is a diehard fan of anime, manga and the otaku culture. Yuuto promises to keep her secret hidden and the two become close friends. Yuuto does his best to help Haruka with her secret hobby while developing his relationship with her.
(Source: Wikipedia)