Angel's 3Piece!

Kyō Nukui is a shut-in high schooler with a love for music, often posting his music online under the fake name of HibikiP. One day, an anonymous sender wants to meet him at a park, to which Kyō agrees, thinking it to be a middle-aged man interested in discussing music like him. However, the anonymous sender turns out to be three elementary school girls Jūn Goto, Nozomi Momijidani, and Sora Kaneshiro, who request that he play his music with their band in an upcoming concert. They perform first for him, and despite being highly impressed with their musical skills and vintage instruments, is still unsure about his decision.

Kyō discovers that Jun and the others are classmates of his younger sister Kurumi, but for some reason do not get along well with the other kids at school. He also finds out that his childhood friend Sakura Toriumi is also an orphan from Little Wing, and asks him to keep it a secret.

The concert is a success, and Kyō and the girls next step is to gather more public to make a steady income from their gigs. By suggestion of a friend, Kyō decides to make a PV of them for advertising.

Kyō is invited along the girls of Lien de Famille by his online friend Yuzuha Aigae to hold a concert on a resort island, unaware of her true intentions.

Kyō discovers that his online friend was not Yuzuha, but Kiryu Yume, and Yuzuha was acting in her stead. When Kiryu decides to cease all connections with Kyō and the others, they decide to find a way to cheer her up.

Enraged with how much time Kyō spends with the girls of Lien de Famille, Kiryu decides to form her own act with Yuzuha and Kurumis help and challenge them to a duel. In the occasion, Jun expresses her wish to write a music of her own, and Kyō agrees to help her with it.