"ReLIFE" centers on Arata Kaizaki, a 27-year-old man struggling with his career and personal life after quitting his first job. Feeling directionless, he encounters Ryo Yoake, an employee of the ReLIFE Research Institute, who offers him a unique opportunity: participate in a social experiment that will make him appear 17 years old again. Arata agrees, and under the alias of a high school transfer student, he is sent back to relive his senior year of high school. The experiment aims to help him reevaluate his life choices and regain a sense of purpose.

Arata enrolls in a new school, where he meets a diverse group of classmates, including Chizuru Hishiro, a highly intelligent but socially awkward girl; Kazuomi Oga, a popular and athletic student; Rena Kariu, a cheerful and outgoing classmate; and An Onoya, a lively and observant girl who is secretly Ryo’s coworker, tasked with monitoring Arata’s progress. As Arata navigates the challenges of high school life, he forms meaningful connections with his peers, often drawing on his adult experiences to help them with their personal struggles.

The narrative explores themes of second chances, self-discovery, and the impact of relationships on personal growth. Arata’s interactions with his classmates gradually reveal their insecurities and aspirations, while his own past mistakes and regrets come to light. Chizuru, in particular, becomes a central figure in his journey, as her struggles with social isolation mirror his own feelings of inadequacy. Their evolving relationship highlights the importance of empathy and understanding in overcoming personal challenges.

As the experiment progresses, Arata begins to reflect on his past decisions and the opportunities he squandered. The series delves into the complexities of adolescence and adulthood, contrasting the idealism of youth with the realities of adult life. The ReLIFE experiment serves as a catalyst for Arata’s transformation, allowing him to confront his fears and rediscover his potential.

The story concludes with Arata completing the experiment, his memories of the past year erased from the minds of his classmates. However, subtle hints suggest that the bonds he formed may still influence their lives in unexpected ways. "ReLIFE" balances humor, drama, and introspection, offering a poignant exploration of redemption and the enduring impact of human connections.