Socially inept and often desperate, the series chronicles her various attempts to try to be more popular at her school, Makuhari Shuuei High School. She is 15 years old at the time of the series' debut and was born towards the end of February of either 1994, 1997, or 1998.
Tomoko started off very excited about high school. After all, she had had over 50 years of dating experience with over 100 boys in otome games, and she could not have been more enthralled with the years of popularity her secondary education was bound to bring! However, after going two months without speaking to anyone in her class, Tomoko is baffled by her continuing lack of notoriety and becomes more determined than ever to gain her peers' approval. In both the manga and anime, Tomoko debuts looking up the definition of "unpopular girl"--"mojyo" spelled in the English titles later--on the internet only to discover she fits all of the criteria! In the anime opening titles, she is depicted as a prisoner having her pictures taken wearing a placard that identifies her as "mojyo" in English letters.
One of the ways Tomoko plans to rehabilitate herself is through daily talks with her brother, Tomoki Kuroki, who begrudgingly agrees to this unusual request. She also frequently spends times with her grade school friend, Yuu Naruse, whose favorable social status is often coveted by Tomoko.
Though she has little to no success at first, she has slowly gained some of her peer's respect. In her second year she makes a new friend, Nemoto, in her class whom she talks to. She also befriends a member of the culture festival committee, though she has had very little interaction with the latter. It is also apparent that she has become slightly more confident in dealing with other people in social interaction. For example, she can hand over her home economics ingredients which she could not do previously. Unfortunately, her attempts to act "cool" often have disastrous results. Stuck under a covered bus stop with two boys, she attempts scatological humor only to realize how awkward and weird it is. In a way, her panic when confronted by social situations can lead her to speak without a filter.
In the chapters covering her second year of high school, she has, perhaps unwittingly, collected a group of friends. Most, like Masaki Yoshida, Nemoto, and Yuri Tamura have their own issues dealing with people. However, the very popular "Class Mom" Asuka Katō also treats her kindly. By her third year, Tomoko has even acquired an underclasswoman kouhai and, unbeknownst to her, a girl who has developed some type of crush on her.
