"Kirakira 100%" is a romantic comedy manga that centers around the lives of high school students navigating love, friendship, and self-discovery. The protagonist, Aoi Kiryuu, is an ordinary high school boy with a passion for photography. His life takes an unexpected turn when he encounters a mysterious girl named Hikari Hoshino, who exudes a radiant charm that captivates him. Hikari is a member of the school's idol group, known for her dazzling performances and cheerful personality. Aoi becomes determined to capture her essence through his camera lens, leading to a series of interactions that deepen their connection.

As the story progresses, Aoi's feelings for Hikari grow, but their relationship is complicated by the presence of other characters. Yuki Saotome, a childhood friend of Aoi, harbors unspoken feelings for him, creating a love triangle that adds tension to the narrative. Meanwhile, Hikari's own struggles with her identity and the pressures of being an idol come to light, revealing a more vulnerable side to her seemingly perfect life. The manga explores themes of ambition, self-worth, and the complexities of young love as the characters grapple with their emotions and aspirations.

The plot is driven by the evolving dynamics between Aoi, Hikari, and Yuki, as well as the supporting cast, which includes fellow students and members of the idol group. Each character contributes to the story's progression, with their personal arcs intertwining with the central romance. The manga balances lighthearted moments of humor and camaraderie with poignant scenes that delve into the characters' insecurities and growth. Through its exploration of relationships and personal challenges, "Kirakira 100%" presents a heartfelt portrayal of adolescence and the pursuit of dreams.