S1 • E1
A boy named Atsuhiro "Wien" Maeda transfers into the class and is guided around the school by badminton player Taichi Tanaka. Meanwhile, a girl named Konatsu Miyamoto quits the choir club after becoming tired of not being able to sing and aspires to create a new choir club, of which she'll need five members. After managing to convince her best friend, Sawa Okita, to join and forcing her brother to apply as well, Konatsu tries to convince her other friend Wakana Sakai to join, but she doesn't want to sing for personal reasons.
S1 • E2
Sawa brings Wakana and Konatsu to her house, showing Wakana what happened to Konatsu during last year's recital and getting her sign up for their new club in name.
S1 • E3
As Wakana is approached by a strange foreigner on her way to school, Konatsu once again finds herself short on members as many of them suddenly quit, with the vice principal threatening to dissolve the choir club, along with Taichi's badminton club, unless they can find sufficient members.
S1 • E4
As Konatsu meets the Condor Queens, Wien spots Wakana being chased after by the foreigner, who turns out to be the third member of Condor Queens and an acquaintance of Wakana's late mother, Mahiru. Meanwhile, Sawa starts to become annoyed with Konatsu as she appears to want to spend more time with the Condor Queens than practice for the choir club, threatening to quit if she doesn't take things seriously.
S1 • E5
As the gang show their support to Taichi as he participates in a badminton tournament, Wakana appears to be occupied by the letter she received. The next day, Wakana runs into Sawa's mother, Shiho, who shows her an old photo of Mahiru in high school with the vice principal, Naoko. Remembering how she had often argued with her mother over music before her death due to focusing on her exams, Wakana asks her father to get rid of the piano in her room.
S1 • E6
As Wakana comes down with a cold, Konatsu decides to pay her a visit, reminding Wakana of her promise with her mother to write a song together. Later, Wakana receives a tape from Shiho containing a recording of when Mahiru was in the choir club. The next day, Wakana helps Taichi and Wein with their vocal training before visiting Tomoko and her new baby. Later that day, Wakana learns from her father why her mother kept her illness a secret from her.
S1 • E7
As the club tries to decide what to do for the school culture festival, Konatsu is taunted by her former club members. Konatsu soon learns that, in order to get on the main stage for the festival, they will have to be approved by Naoko. Meanwhile, Sawa is at odds with her father, who sees her ambition of becoming a professional jockey as simply playing around.
S1 • E8
After being checked by the hospital, Sawa is told by her father to quit horseback archery. Sawa later reveals that she was skipping meals as she was attempting to apply for a riding school, but wasn't accepted due to her weight and height. The next day, as Naoko tries to get Konatsu to withdraw her application for use of the stage, Wakana explains what she learned by being able to sing with others, which reminds Naoko of Mahiru. Naoko decides to have the choir club participate in a committee meeting to prove their growth.
S1 • E9
As Konatsu reveals the club will perform a musical drama at the school festival, Wien seems preoccupied by something. Later, Shiho suggests putting on a superhero show at the shopping district and gets Konatsu and the others to play the part of the superheroes, sparking Wien's interest in particular. After that Wakana asks Shiho about how Mahiru went about writing her songs, she suggests asking Naoko, as she previously co-wrote a song with her.
S1 • E10
Despite some initial setbacks, the gang manages to make the superhero show a success. The next day, Naoko calls up Konatsu and the others about their job. Afterwards, Wakana asks Naoko about how Mahiru wrote her songs.
S1 • E11
As the choir club works hard on its musical, Taichi, who is creating background props, tries to recruit a decent painter. As Konatsu tries to get help from the vocal group, she hears from Naoko that the school festival has been canceled as the school is being closed down to make way for new buildings.
S1 • E12
Konatsu pleads with the student council to resume the school festival. The next day, as Wakana visits her mother's grave, she runs into Naoko and shows her the song she and Mahiru wrote together.
S1 • E13
As the gang and their families prepare for the festival, they discover the school gates are closed and the gym has been locked up. As the chairman confronts them, the principal decides to stand up to him and allow the festival to be held.
Wakana Sakai
Konatsu Miyamoto
Sawa Okita
Taichi Tanaka
Wien
Shiho Okita
Naoko Takakura
Principal
Keisuke Sakai
Akio Hanaya