"Re:Stage! Dream Days" is a 12-episode anime series that centers around the journey of a group of high school girls as they pursue their dreams of becoming idols. The story is set in the fictional Yoba Academy, a prestigious school known for its performing arts program. The protagonist, Mana Shikimiya, is a reserved and academically focused student who initially has no interest in extracurricular activities. However, her life takes a turn when she encounters Mizuha Kizaki, a cheerful and determined girl who dreams of reviving the school's dormant idol club, KiRaRe.

Mizuha convinces Mana to join her in forming a new idol group, despite Mana's lack of experience in singing or dancing. The two recruit additional members: Nagisa Aizawa, a talented but shy dancer; Hiyori Sakuragi, a confident and energetic performer; and Kae Yuki, a skilled musician with a calm demeanor. Together, they form the group KiRaRe and begin their journey to compete in the Prism Stage, a prestigious idol competition that could elevate their careers.

The narrative explores the challenges the group faces as they balance their personal lives, school responsibilities, and the rigorous demands of idol training. Each character brings unique strengths and struggles to the group, contributing to their growth both individually and as a team. Mana, in particular, undergoes significant development as she learns to step out of her comfort zone and embrace her passion for performing. The series also delves into the dynamics of friendship, teamwork, and perseverance, as KiRaRe works to overcome obstacles and prove themselves on the Prism Stage.

Throughout the series, KiRaRe competes against rival idol groups, each with their own distinct styles and motivations. These interactions highlight the competitive yet supportive nature of the idol industry. The story culminates in KiRaRe's participation in the Prism Stage finals, where they aim to showcase their hard work and dedication. The series concludes with a sense of accomplishment and optimism, leaving room for the characters' continued growth and future endeavors.