The introduction of the consumption tax in 1989 led to a review of Japan's automobile tax system, which increased the tax burden on vehicles that fall under Japan's unique kei car standards. As a result, the Japanese kei car market was shrinking in the early 1990s. To break out of this situation, SUZUKI introduced the Wagon R (first generation CT21S/51S/CV21S/51S models) in 1993 as an innovative minicar with a new concept inspired by the American minivan. Prior to the introduction of the Wagon R, minicars, which were limited by Japanese regulations in terms of body size and displacement, were generally superior in terms of maintenance cost and have a small turning circle, but had limited interior space. In order to improve the interior space, which had been a disadvantage of minicars, SUZUKI raised the overall height of the body significantly higher than that of conventional minicars to create more interior space, and installed a double-layered floorpan to provide anti-vibration and soundproofing measures. And taking advantage of the fact that the seat position becomes higher, by making the occupants sit in an upright position, more leg space was gained. As result, the first-generation Wagon R, with its ease of use and good space utility, won the support of a wide range of users in Japan and quickly became the best-selling car in the country. On the other hand, the success of the Wagon R spawned a number of strong rivals in the Japanese market with similar concepts to the Wagon R, such as the DAIHATSU MOVE. As a result, the Wagon R's followers, the high wagon type minicars, became the majority in the Japanese market, where minicars account for close to a majority of sales, and had a significant impact on the way Japanese automakers made their cars. In order to compete with its powerful rivals, SUZUKI continued to prioritize the introduction of its latest technology in each model change, and despite numerous model changes, it maintained its position as the best-selling car in Japan. This vehicle is the third-generation Wagon R, which was introduced in 2003. The platform was renewed from the previous generation Wagon R, and new SUZUKI technologies were aggressively introduced, such as the use of a direct injection turbo engine.

The story is set in Tokyo, where an old school right in between the neighborhoods of Akihabara, Kanda and Jinbocho is in danger of consolidation and closure. Nine girls, centering Honoka Kosaka, have stepped up to defy the imminent danger facing their school. “If we want to protect our beloved school, we need to do what we can? we need to become idols!” Hoping against hope there’s something they can do about this, the girls strive to become famous, spread the word about their school, attract more students, and save the day. Now their “School Idol Project” begins to make their dreams come true! “Make our dreams come true!”

The No.1 idol in the universe. She is the head of the idol club at　Otonokizaka Academy, to which μ's belongs. She is a third-year student, and has founded and served as the head of the idol research club in the past. She is more passionate and devoted to idols than anyone else. Before joining μ's, she studied as a school idol by herself. Therefore, she has been able to set the direction of μ's as a school idol group by providing guidelines for the other members of μ's who are not familiar with the school idol scene. She is also in charge of comedy in "μ's" and plays the role of straight man to other members. She is raising in a single parent family. She have two younger sisters and a younger brother, and takes care of them on a daily basis. She is good at cooking. Her signature phrase is "Niko Nico Ni".

She is a third-year student at Otonokizaka Academy. She is the vice student council president of Otonokizaka Academy and a good advisor to the other members of μ's. She has a strong spiritual sensitivity and is good at fortune-telling. When she was a child, she had to repeatedly change schools due to her parents' work, she did not fit in well at school and had no friends for many years. Therefore, She has long wished to make friends in high school. She has been providing various advice and support for Honoka's plan to prevent the consolidation of Otonokizaka Academy since before she joined μ's. The name "μ's", the school idol group of Otonokizaka Academy, was the brainchild of Nozomi.

A third-year student at Otonokizaka Academy. She is the student body president of Otonokizaka Academy and a dance coach for μ's. She was raised in Russia, the home of ballet, where she received a gifted education in ballet from an early age, and although she had great hopes for her future as a ballerina, she failed in her career. Her dancing ability is at a professional level. At first, Eri was skeptical of Honoka Kousaka's plan to increase the number of applicants to Otonokizaka Gakuin and prevent the consolidation of Otonokizaka Gakuin through publicity for the school idol program, but Honoka's enthusiasm inspired her to join μ's herself. Her grandmother is Russian, and she is fluent in Russian. Her habit is to say "Harasho" in Russian.