Muse

μ's (pronounced "Muse") is a school idol group in the Love Live! School Idol Project anime. They're the school idol group of Otonokizaka High School. The group consists of nine members and was initially formed with the purpose of preventing their school from closing.

Songs
All of μ's songs and albums can be found here.

Season 1
Although not as an official club, the group is formed at the end of Episode 1 when Kotori brings Umi to show her Honoka practicing to become an idol, and they both decide to join Honoka. The club registration, however, is rejected by the student council president, Ayase Eli, because of both their intention and the lack of members. However the vice president, Toujou Nozomi, advises them to find at least five members, the requisite number to officially form a club.

They perform their first live concert in the school auditorium and sing the song "Start:Dash!!" in Episode 3, composed by Maki with the original lyrics by Umi. Hanayo turns up to the concert, followed by her friend Rin and they are the main audience at the concert. Nico, Maki, Nozomi, and Eli, who records the whole performance, secretly listen to their concert. It is later uploaded to the internet by Eli.

In Episode 4, the group gains three more members: Hanayo, Rin and Maki. At first, they seem to be reluctant to join the group, but after some time, they finally join the group. In the next episode, Episode 5, one more member is added to the group: Yazawa Nico. She tried to dismiss the group due to her jealousy of their success, but when all of her attempts failed, she decided to join the group instead. This make the group consist of seven idols, commemorated with a single named "Korekara no Someday" (これからのSomeday).

Much later in Episode 8, the group finally get another two members, Nozomi and Eli, making the count increased to nine. This, as explained by Nozomi, fulfilled the myth behind their name "μ's," which actually originated from the nine Greek goddesses of music. This moment is then celebrated with their full member debut during the school festival. The song they sang was "Bokura no LIVE, Kimi to no LIFE (僕らのLIVE,君とのLIFE)".

In Episode 11, μ's has reached rank #19 on the school idol rankings site, making them eligible for the Love Live! tournament. This puts pressure on the group, but mainly Honoka, who begins to overwork herself. After performing "No Brand Girls" on the rooftop for a performance, Honoka collapses.

In Episode 12, after the incident from the previous episode, μ's has withdraw from the Love Live! tournament. Later in the episode, they discover that the school has been saved, causing them all to celebrate. But when Umi announces Kotori is leaving for the rest of high school to a fashion boarding school, μ's is shock, but Honoka gets angry. Later on the rooftop, μ's tells Honoka that they'll be having one last concert before Kotori goes. However, Honoka says that there's no point in performing anymore, now that the school is saved, and that it's impossible to go against the idol group A-Rise. Honoka then says she quits, but before she could leave, Umi grabs her and slaps her on the cheek, and says she didn't think she was that kind of person and that she's the worse there is.

In the final episode, Episode 13, Honoka and Umi forgive each other, and Kotori decides not to go to the boarding school after being stopped by Honoka. At school, the girls perform "Start:Dash!!," this time with the auditorium full. Afterwards, Honoka tells the audience to say "μ's Music Start!" and μ's are in the school idol group rankings again.

Trivia

 * In reality, the group name "μ's" was decided through a cellphone poll by fans, one month after the release of their first single Bokura no LIVE, Kimi to no LIFE (僕らのLIVE,君とのLIFE) in August 2010.
 * Other polls also determined the names of the mini idol units: Printemps, BiBi, and Lily White.
 * Based on cellphone polls, the member with the most votes would be given the center position of the next music video. For example, Nico was the center of Natsuiro Egao de 1, 2, Jump! (夏色えがおで1,2,Jump!?) because she won a poll.
 * Polls also determine the idols' hairstyles and costumes for the music video.