Monthly Girls' Nozaki-kun

Chiyo Sakura, age 16, tells her crush Umetaro Nozaki that she is his fan, but he responds by giving her his autograph. She then says she wants to be with him always, so Nozaki invites her home and gives her some "beta work", which after several hours, she realizes she is doing inking for him. She realizes he is a shojo manga artist who is published in a magazine she has bought. Later, they think of romance ideas such as making a guy a delinquent but should obey the laws, and taking a girl home with a bicycle. Nozaki invites Sakura home but he has a tandem bicycle, so they see if any of the situations are conducive to romance. After seeing him interact with some cats, Sakura tries to confess her love again, but gets another autograph. Nozaki introduces Sakura to his friend.

Nozaki introduces Sakura to his friend Mikoto Mikoshiba, a popular and flirtatious guy who Sakura soon learns is actually painfully shy and is often ashamed of his own words. He spends a session at Nozaki's place eagerly waiting for Sakura to ask him for help although he is too shy to prompt her. Sakura learns that Mikoshiba's artistic specialty is adding background decorations such as flowers, and she discovers that Mikoshiba is Nozaki's model for the heroine of his manga. Nozaki later asks Sakura if she has any friends who might fit in a shojo manga. Sakura introduces them to Yuzuki Seo, a girl who the guys discover has a habit of being insensitive and oblivious (not reading the atmosphere). However, she has an angelic singing voice, of which she is nicknamed the Glee Club's Lorelei.

Mikoshiba introduces to Sakura and Nozaki his best friend, Yū Kashima, who is known as the school prince, but is actually a girl. She is a member of the acting club and is really popular among the girls. However, she is a bit dense and acts idiotic sometimes that her senior at acting club Masayuki Hori will scold and even physically beat her. After helping Hori paint some sets, Sakura discovers that he is the one who does backgrounds for Nozaki's manga. When Mashima sees Hori with Nozaki, she gets a bit jealous. Nozaki later has Hori and Sakura role-play some parts, during which Mikoshiba also gets involved.

Mikoshiba asks Nozaki if he can stay over in order to seek his advice regarding girls, however the "girls" turn out to be heroines of a dating simulation game. As they try out the game, they realize that the protagonist's best friend, Tomoda, has been caring for him throughout his adventures, which prompts Nozaki to make a story about their friendship, which appears to Sakura to be a Boy's Love-genre story. Later, Mikoshiba is invited to attend a mixer but is too shy to know what to do there, so Nozaki and Sakura practice with him.

Nozaki frantically cleans his apartment for his editor, Ken Miyamae, who appears and leaves so quickly that Sakura thinks he does not like Nozaki. However, Nozaki praises him in comparison to his previous editor Maeno, with whom he had bad experiences. Sakura meets Nozaki's neighbor, Yukari Miyako, who also draws manga in the same magazine, and later meets Maeno himself. When Ken tells Nozaki that the heroine of the manga should express more feelings, Nozaki pretends to act like the heroine for the day by giving lunches to his friends and carting Kashima away from a mob of livid girls. He concludes that Mamiko needs to study more and draws that into his storyboards.

Nozaki sees Hirotaka Wakamatsu, his junior from middle school when they were on the basketball club. Wakamatsu tells Nozaki about being stressed out and unable to sleep because of Seo's antics, however, when he hears a recording of Lorelei's singing, he immediately falls asleep and feels refreshed. Using Nozaki's shōjo manga as a basis, he confronts Seo, but she interprets his actions as gestures of friendship. Later on, Nozaki gets a fever and sends the text message "SOS" to Hori, Sakura, and Wakamatsu. The three team up to help Nozaki with his manga, but are challenged with the task of applying screentones.

When Nozaki agrees to go with Sakura on his day off, Sakura thinks of it is a date situation, but Nozaki uses the time to get more manga ideas. They go to the mall and encounter Mikoshiba at a doll store. Later on, Mikoshiba volunteers to model for the art club.

Kashima has been driving Hori crazy with her antics, but she gets confused when she discovers that Hori and the guys have been reading Yumeno’s shojo manga and taking it rather seriously. Hori challenges Nozaki to do some backgrounds, but Nozaki frustrates him when he does not get the perspective right, placing boxes under his characters to compensate. Thinking Hori aspires to be a princess, Kashima replaces his clothes with something more feminine. When Hori collapses during a rehearsal, Kashima carries him to the nurse’s office while wearing a bull mask.

When Sakura and Nozaki both forget to bring umbrellas for a rainy day, Nozaki takes the opportunity to gather romance ideas about umbrella sharing for his manga. After Seo gives them her umbrella, Chiyo cherishes the walk from school. Later, the two observe how Miyako deals with editor Maeno’s crazy recommendations, and tell her to stand up to him.

Hoping for some ideas for his side characters, Nozaki has Wakamatsu accept a movie date with Seo. When Hori suggests doing a musical production, Kashima scrambles for help as she is tone-deaf and cannot sing. During rehearsals, Hori duels Kashima, but when Mikoshiba is volunteered to do a part, Hori realizes he resembles Mamiko.

Nozaki wants to create some excitement within the manga's story, and for reference, he tries a variety of strategies to surprise Sakura. Later, Mikoshiba, Hori, and Wakamatsu get caught in the rain, and all sleep over at Nozaki's apartment for shelter. Nozaki begins to use the others as a reference point for another chapter of the manga.

Chiyo tries to advance her relationship with Nozaki when she finds that she still has not given him the chocolates she had for Valentine’s Day. Chiyo, Nozaki and their friends attend a summer festival where Chiyo is reminded of the time when she and Nozaki first met.