"Days: Tōin Gakuen-sen" is a sports anime centered around soccer, adapted from the manga series "Days" by Tsuyoshi Yasuda. The narrative primarily revolves around Tsukushi Tsukamoto, a shy and unathletic high school student who becomes unexpectedly drawn into the world of competitive soccer. Despite his lack of experience, Tsukushi joins the soccer team at Seiseki High School after being inspired by his classmate, Jin Kazama, a talented and passionate soccer player. The series explores Tsukushi's growth as he navigates the challenges of teamwork, perseverance, and self-improvement within the high-stakes environment of high school soccer.

The story begins with Tsukushi's introduction to soccer through a chance encounter with Jin, who convinces him to join the team despite his initial reluctance. Tsukushi's determination to improve, coupled with his unwavering effort, earns him a place on the team, even as he struggles to keep up with his more skilled teammates. The series highlights the dynamics of the Seiseki High soccer team, focusing on their journey through regional and national tournaments. Key matches are depicted with intense detail, showcasing the strategies, rivalries, and emotional highs and lows of competitive play.

Central to the narrative is the relationship between Tsukushi and Jin. Jin, a prodigious player with a strong sense of leadership, serves as both a mentor and a rival to Tsukushi. Their contrasting personalities—Tsukushi's humility and Jin's confidence—create a compelling dynamic that drives much of the story's emotional core. Other notable characters include Hisahito Mizuki, the team's captain and a calm, strategic player; Atsushi Kimishita, a sharp-tongued but skilled midfielder; and Nobunari Oda, a cheerful and supportive teammate. Each character contributes to the team's chemistry and growth, with their individual arcs intertwined with the broader narrative of Seiseki's quest for victory.

The series also delves into the challenges faced by the team as they confront formidable opponents, such as Tōin Gakuen, a powerhouse school with a reputation for producing elite players. The rivalry between Seiseki and Tōin becomes a focal point, particularly through the character of Hiroyuki Kira, Tōin's star player and Jin's former teammate. This rivalry adds depth to the story, emphasizing themes of ambition, rivalry, and the pursuit of excellence.

Throughout the series, the emphasis remains on the personal and collective growth of the characters, both on and off the field. Tsukushi's journey from an inexperienced novice to a valued team member serves as the emotional backbone of the story, while the broader narrative explores the camaraderie, sacrifices, and determination required to succeed in competitive sports. The series balances intense soccer matches with moments of character development, creating a well-rounded portrayal of the challenges and rewards of pursuing a shared goal.