"More Than a Married Couple, But Not Lovers" centers on a unique school program designed to teach students about the responsibilities and dynamics of marriage. High school students are paired randomly and tasked with living together as "married couples" for a set period. Their performance is evaluated based on their ability to maintain a harmonious relationship, complete household chores, and demonstrate mutual understanding. The story primarily follows Jirou Yakuin, a reserved and somewhat awkward student, and Akari Watanabe, a confident and popular girl who initially clashes with Jirou due to their contrasting personalities.

Jirou harbors feelings for his childhood friend, Shiori Sakurazaka, who is kind-hearted and gentle but struggles to express her emotions. Akari, on the other hand, is determined to pair with her crush, Minami Tenjin, a charming and athletic classmate. However, due to the program's random pairing system, Jirou and Akari are forced to live together, creating a tense and often comedic dynamic as they navigate their differences.

As the story progresses, Jirou and Akari gradually develop a deeper understanding of each other, moving beyond their initial animosity. They begin to support one another in their personal struggles, with Jirou helping Akari confront her insecurities and Akari encouraging Jirou to be more assertive. Their evolving relationship blurs the line between their assigned roles and genuine emotional connection, raising questions about the nature of their bond.

The series explores themes of self-discovery, communication, and the complexities of relationships, both romantic and platonic. Through their shared experiences, Jirou and Akari learn valuable lessons about trust, compromise, and the importance of emotional honesty. The narrative also delves into the challenges faced by the supporting characters, such as Shiori's quiet longing for Jirou and Minami's own struggles with his public persona.

"More Than a Married Couple, But Not Lovers" balances humor, drama, and heartfelt moments, offering a nuanced portrayal of adolescence and the trials of navigating relationships in a structured yet unpredictable environment. The characters' growth and interactions drive the story, creating a compelling exploration of love, friendship, and the gray areas in between.