" The Red Threads of Science" is a complex system implemented by Japan in a futuristic society to combat low birthrates and encourage successful marriages. At the age of 16, young people are assigned marriage partners based on compatibility calculation by the government. Those who disobey the arrangement face serious consequences. Yukari Nejima, who considers himself an average teen, sees this as his best chance at leading a fulfilling life. However, his infatuation with his long-time crush and classmate, Misaki Takasaki, prompts him to defy the system and confess his love. After initial reluctance, Misaki reciprocates his feelings in a moment of passion. Their relationship is cut short when Yukari receives his marriage notice. His assigned partner, Ririna Sanada, becomes intrigued by his forbidden romance, plunging Yukari into a tumultuous web of love and deceit.