Featuring stories from the manga not adapted in the main anime.

Junior high school student Kimichika Haijima moves back to his hometown, Fukui, after causing trouble in the Tokyo Junior High School volleyball club. There, he is reunited with his childhood friend, Yuni Kuroba, who possesses outstanding physical abilities, but is vulnerable under pressure. Haijima, with his overwhelming passion and talent for volleyball, forms an ace combination with Kuroba. The two enroll at Seiin High School, where they join the volleyball club. Awaiting them are the 163 cm hot-blooded captain Shinichirou Oda, the talented and sharp-tongued vice-captain Misao Aoki and his third-year pair, and second-year students, including Akito Kanno, who is always wearing long sleeves due to his allergy to sunlight. The newborn team breaks its former shell of weakness and becomes Fukui's rising star. This is a certain team's journey to victory, with a series of fascinating rivals standing in their way.

Freshman Kaho Nikaidou is from an influential family, and as such, no one has ever said anything even remotely mean to her, for fear of incurring her household's wrath. Wishing to be around people who will not treat her as special because of her background, she leaves home to live at a dormitory for her new school year. Shortly after arriving, Kaho accidentally wanders into traffic and is saved by a tall, handsome stranger. When she asks for his name, he tells her she is weird and walks away. Having finally met the only person to ever say an unkind word to her, Kaho falls head over heels for her savior. After meeting her rescuer yet again and discovering that his name is Kanade Takahashi, she confesses her love to him. Kanade says he would like for them to be a couple, but that Kaho may not want to date him after she finds out his secret. To her shock, Kaho discovers the startling truth: Kanade is a fifth grader! Deciding that she can't date a fifth grader, Kaho intends to break up with him. But as she spends more time with Kanade, she begins to care for him even more and continues dating him. Hatsukoi Monster follows Kaho's first steps into love with Kanade, her immature, yet kind, fifth grade boyfriend.

In 2008, the Japanese government began hunting people who identify as otaku in an effort to protect the country's culture. In just one week, the enforcement agency known as the SSC captured almost every otaku by force and confiscated their memorabilia. One passionate man calling himself Otaku Hero refuses to allow this agency to do as they please: he raises a resistance army made up of other displaced geeks who band together to help defend their culture. Three years later, the fires of rebellion wane as all hope seems lost for otakus. Spurred on by his ally—the magical girl Anarchy—Otaku Hero commands the resistance in an effort to reunite Anarchy with the other two other magical girls: Blue and Pink. By combining the power of this trio, the resistance may be able to defeat the SSC and save otaku culture for everyone.