Otonokizaka Academy is announced to be closing down after everyone graduates due to lack of applicants, much to the shock of second year student Honoka Kousaka, who loves the school. As she and her classmates Umi Sonoda and Kotori Minami try to think of a way to make the school more attractive to prospective students, Honoka is surprised that her younger sister Yukiho wants to go to a different school, UTX, instead of Otonokizaka. As Honoka decides to investigate UTX, she finds it attracts a lot of students due a school idol group known as A-Rise. Honoka decides that the best way to save her school is to start an idol group themselves, though Umi isn't keen on the idea. As Honoka becomes downhearted, she spots a talented singer and pianist and redoubles her efforts, whilst Umi inevitably gives in and joins Kotori in partaking in Honoka's idea. Despite their request to start an idol club being rejected by the student council president, Eli Ayase, Honoka remains determined to make it work.

Honoka manages to get permission to use the auditorium for a concert in a month's time, although Umi has doubts that they'll be ready in time. Unable to think of a name for their group, Honoka holds a contest for the name instead before realizing they do not actually have a song to practice. As Umi reluctantly agrees to write lyrics, she puts Honoka and Kotori on an exercise regime to build up their stamina. As Honoka unsuccessfully attempts to get the girl from before, Maki Nishikino, to compose songs for them, Eli warns her that her idol plan could backfire and damage the school's reputation further. Honoka perks up when she hears the class is supporting her, as well as receiving a name for their group, μ's. Honoka once again approaches Maki, showing her how serious an idol's work is and giving her the lyrics Umi wrote. After a little advice from the student vice-president, Nozomi Toujou, she sends Honoka a CD of the song she composed from Umi's lyrics whilst also anonymously voting for μ's on an idol ranking site.

On the day before the concert, Umi starts to get cold feet about performing in front of others. To get her used to other people, Honoka and Kotori get Umi to hand out fliers to help build her confidence. Umi has some reservations about the costume, but Honoka manages to convince her to make sure all their efforts don't go to waste. However, on the day of the concert, no one shows up as all the freshmen are busy checking out the other clubs. Just as Honoka is about to break down over her wasted efforts, a nervous girl named Hanayo Koizumi shows up to see the concert, prompting Honoka to go ahead with the performance, which soon attracts a small, but very much appreciated crowd. When asked by Eli about what they'll do next, Honoka insists they'll keep on performing so they can eventually fill up the auditorium.

As Hanayo debates whether she should join the idol club, which needs five members to become official, she asks her friend, Rin Hoshizora, if she would be willing to join with her, although she declines as she doesn't have enough confidence in her femininity. Later that day, Hanayo visits Maki's house to return her dropped Student ID, where she explains how she'll probably have to quit music in order to study medicine and inherit her family's hospital, but says she'll support Hanayo should she decide to become an idol. Afterwards, Hanayo comes across Honoka's shop, where Umi and Kotori are also visiting as they notice a recording of their performance has gained a fair amount of views on the internet. Mentioning that even they have their flaws, the girls formally invite Hanayo to join the club, asking her to think it over. Noticing her shyness in class, Maki decides to help Hanayo learn to speak loudly. After receiving a push from both Maki and Rin, Hanayo finally agrees to join the idol club, whilst Maki and Rin also decide to join.

Honoka and Kotori are confronted by a curious girl named Niko Yazawa, who tells them they should break up. Meanwhile, as the rainy season causes the club to think about where they can practice, Honoka realizes that they could try and form an official club now they have enough members. Just then, they catch Niko trying to steal their food and insult their lack of professionalism. The girls learn from Eli that they can't form their idol club as there is already an Idol Research Club, whose sole member turns out to be Niko. After Niko rejects their offer of merging the groups, assumedly based on their lack of personas, student vice-president Nozomi Toujou explains how Niko had previously attempted to become a school idol but set the bar too high, leading it to fall apart. After thinking about it, Honoka comes up with the idea that they should all join the Idol Research Club to learn how to improve μ's, inviting Niko to join the group as their coach.

Whilst shooting interviews for each of the clubs, Nozomi suggests to the group that they shoot a new music video now that they have more members. During the interviews, Nozomi becomes curious as to why Honoka is the leader of μ's when she doesn't seem to do anything. Thus, the discussion soon turns to who should be the leader and center in the group, but they can't decide on who is the most worthy. Thus, Niko suggests that the decision be settled by a sing and dance contest at a karaoke place, though her plan to outshine everyone doesn't go very well as everyone ends up with similar scores. Honoka then suggests that they don't really need a leader and should just have everyone taking turns to sing, although the others secretly agree that Honoka is the most leader-worthy person. As the girls complete their new music video, Nozomi prompts to Eli that she should be the one to help them.

Hanayo informs the gang of a school idol tournament called Love Live in which the top 20 school idol groups from across the nation compete against each other. Needing the school's permission to enter, the group go to ask the chairwoman for permission, and despite Eli's objection, she approves of their entry on the condition that none of them fail a subject in the upcoming exams. This puts a lot of pressure on Honoka, Rin and Niko, who have generally bad grades. Umi and Kotori decide to help Honoka study whilst Hanayo and Maki help Rin and Nozomi helps Niko. Later that day, Umi comes across Eli's little sister, Arisa, a fan of μ's who reveals Eli shot a video of their live performance and uploaded it to the internet. When confronted about why she refuses to acknowledge μ's, she simply responds that she considers all school idols amateurs. As Umi asks Nozomi about why Eli would think that way, she reveals that Eli used to be a talented ballerina. Rather than being deterred by this, Umi becomes determined to ask Eli to teach the group how to dance like her. After the exams finish and everyone manages to pass, Honoka overhears the chairwoman tell Eli that the school will stop accepting new students next year and be shut down.

The chairwoman clarifies the school will be closed down if their upcoming open day is received negatively. As Eli tries to think of ways to attract potential students besides μ's, Umi suggests to the group that they should get Eli to teach them how to dance. Eli eventually agrees to help them out and starts putting them through some intense training, surprised to find them willing to put through with it despite the roughness of it all. As Eli becomes conflicted by what she should do, Nozomi tells her that should do what she wants to do instead of what people expect her to do. Eli breaks down and says she wants to join μ's but doesn't feel she is able to do so. Nozomi informs the others, who formally invite her to join μ's as one of their members. Eli finally becomes honest with herself and joins the group alongside Nozomi, who reveals she was the one who came up with the group's name. The complete group performs at the open day to a pleased crowd.

The success of the open day helps bring the faculty to reconsider the closing of the school, as well as earning the group an expansion to their club-room. After the group manages to reach 50th in the rankings, they visit Akihabara where they find they are already being featured on merchandise. Upon discovering a photograph of Kotori in a maid's outfit among the goods, they learn that Kotori has been secretly working part-time at a maid café after school to build her confidence. Eri decides Akihabara would be the perfect place to hold a live performance, assigning Kotori to write a song about Akiba culture. However, Kotori struggles with coming up with lyrics, which soon has an impact on her studies. In order to help her out, Honoka and Umi join her at the maid café. Recalling the feelings she gets whenever she works in Akiba, Kotori is able to come up with some lyrics which help make the performance a success. As Honoka assures Kotori that they'll be together forever, an air mail letter arrives in Kotori's postbox the next morning.

Honoka suggests that the group go on a training camp to the beach, with Maki coerced into letting them use her family's vacation home. Wanting to break down the barriers between underclassmen and upperclassmen, Eli puts in a rule that no one is allowed to call their upperclassmen with honorifics 'senpai' for the duration of the trip. From this rule, almost all able to do this, except Hanayo, who still sometimes spontaneously called her upperclassmen with honorifics 'senpai'. The girls spend the day playing around on the beach, though Eli and Nozomi are quick to notice Maki doesn't seem to be participating. After dinner and a bath, Nozomi helps Maki become more sociable by initiating a pillow fight. At the end of this trip, somehow, they manages to fully breaks down the barriers between the upperclassmen and underclassmen in the club.

μ's manages to make it to rank 19, making them eligible to apply for the Love Live! tournament, putting pressure on them to keep their position. However, things don't go their way when they are unable to secure a spot on the auditorium for the upcoming school festival. Honoka suggests that they instead hold their performance on the school rooftop where they train, which the others agree too. Meanwhile, Kotori seems to be preoccupied by the letter she received, not being able to find an opportunity to discuss it with the others. As Kotori calls Umi on the night before the festival to tell her what's bothering her, Honoka ends up overexerting herself, ending up with a fever on the day of the festival, but she forces herself to come to school anyway. Despite the rain, the concert goes ahead, but after the first song finishes, Honoka suddenly collapses due to her fever.

As Honoka recovers from her fever, she becomes depressed when the others tell her they've withdrawn their entry from Love Live, which is inevitably won by A-Rise. After Honoka recovers and is eventually cheered up by the others, the group are pleased to learn that the school has gathered enough applicants to stay open for another year. Meanwhile, Kotori still hasn't brought herself to tell Honoka about the decision she had made. Unable to let her keep it a secret any further, Umi announces to the others that Kotori will be leaving in two weeks to study fashion abroad. As Honoka questions Kotori about why she never told her, she learns she was intending to tell her following the live performance, but got put off following her accident. Honoka then becomes deperessed, feeling guilty for not noticing her feelings due to her focus on Love Live. The group suggest putting on one more live performance before Kotori leaves, but Honoka doesn't see the point in continuing and says she wants to quit being a school idol, prompting Umi to become angry and slap her.

With Honoka and Umi still not talking to each other, Eli puts μ's on indefinite hiatus so they can think rationally about the situation. As Honoka's friends take her out to cheer her up, Umi visits Kotori, who has also yet to talk with Honoka, trying to see what she truly wants. Honoka later runs into Niko training alongside Rin and Hanayo, stating that even if μ's is on hiatus, she still wants to be an idol because she loves it. Later, Eli visits Honoka, who reminds her of the words that saved her when she was down. Realizing her true feelings, Honoka apologizes to Umi, stating she still wants to become an idol. Making up with her, Umi sends Honoka to get to Kotori before she leaves Japan and convince her to stay, helping her realize her own desire to stay as well. With all nine members reassembled, μ's is reformed and perform together to a filled school auditorium, vowing to keep on pushing forward.