Jiro Yakuin, a reserved third-year high school student, finds himself thrust into the daunting "Practicum for Newlyweds"—a mandatory school curriculum that pairs male and female students to simulate married life, complete with grading based on intimacy and cooperation. Jiro’s primary motivation is to be paired with his childhood friend and
longtime crush, Shiori Sakurazaka, hoping to eventually confess his feelings and turn their innocent bond into romance. However, school politics and a randomized selection process shatter his dreams when he is instead assigned to Akari Watanabe, a charismatic, trendy, and gyaru-style classmate who is the exact polar opposite of his type. Worse yet, Akari is hoping to be paired with her own crush, the popular Minami Tenjin.Realizing a loophole in the system, Jiro and Akari discover that couples with the highest scores midway through the term are granted the privilege to swap partners. Motivated by their respective desires to be with their true crushes, the bickering duo reluctantly agrees to act like a loving, affectionate married couple to game the grading system. They move into a designated
apartment complex and begin sharing a living space, navigating the awkward realities of cohabitation.Initially, their daily routine is defined by explosive arguments, cultural clashes, and defensive walls. Jiro is overwhelmed by Akari’s bold demeanor, while Akari finds Jiro’s introverted nature frustrating. However, as they face the rigorous demands of the practical exam—cooking, cleaning, and managing household finances—their facade slowly begins to crack. They start noticing each other's hidden vulnerabilities, insecurities, and genuine kindness. Akari supports Jiro through moments of social anxiety, while Jiro steps up to protect and care for Akari when she falls ill, proving to be a reliable and deeply empathetic partner.As the weeks progress, the dramatic tension shifts. The simulated marriage begins to feel frighteningly real to both of them. Jealousy flares when they interact with their original crushes, forcing Jiro and Akari to confront the confusing evolution of their feelings. Akari realizes that her affection for Minami is fading, replaced by a deep-seated, romantic attachment to Jiro. Similarly, Jiro finds himself torn between his idealized childhood memories of Shiori and the vibrant, present reality of his life with Akari. By the time the opportunity to switch partners finally arrives, the original goal of swapping is overshadowed by a profound emotional dilemma, leaving both teenagers to question what love truly means.