Three young girls—Akari, Yuki, and Nozomi—meet at a concert and set out to follow in the footsteps of their idol, Reika, and become music stars.

They enroll in the prestigious music school that produced Reika and are placed in the "S class" due to their potential.

While Chance Pop Session could be characterized as a romantic comedy in the shōjo category, it does have some elements of tragedy.

They all love to sing, and when they each find admission forms for a music school overseen by Reika's manager, they do not hesitate to sign up.

Akari and Nozomi recognize each other quickly and soon become close friends, but Jun keeps an aloof and superior attitude and students who were not selected for the S Class soon grow jealous.

Yuki is one of the four members of Class S in the Chance Pop Session anime and the middle sister of the trio.

Her music career started as a street performer who was gaining a fan following before being recruited for Class S. The "Ao" in her name means blue in English, which becomes significant later.

Nozomi is one of the four members of Class S and the youngest sister in the Chance Pop Session anime.

After deciding that Reika has learned all that she can from her, Kisaragi opens a music school and picks the best students for a special "Class S".