In a futuristic society, Japan has implemented a complex system referred to as "The Red Threads of Science" to encourage successful marriages and combat increasingly low birthrates. Based on a compatibility calculation, young people at the age of 16 are assigned marriage partners by the government, with severe repercussions awaiting those who disobey the arrangement. For Yukari Nejima, a teen that considers himself average in every way, this system might be his best shot at living a fulfilling life. However, spurred by his infatuation for his classmate and long-time crush, Misaki Takasaki, Yukari defies the system and confesses his love. After some initial reluctance, Misaki reciprocates his feelings in a moment of passion. Unfortunately, before the two can further their relationship, Yukari receives his marriage notice. He is then thrown into a confusing web of love and lies when his less-than-thrilled assigned partner, Ririna Sanada, becomes fascinated with his illicit romance. Lies are forbidden and love is doubly forbidden. In the near future, when young people in Japan turn sixteen, they are assigned a marriage partner by the government. People don't have to go through the trouble of looking for someone, and everyone accepts that the country will find a compatible partner to make them happy. Yukari Nejima is fifteen years old. He lives in a small corner of the country, and just can't seem to get ahead in life. Both academically and athletically he's below average. But within him, he hides a heart burning with passion! In this world in which love is forbidden, what will happen to him when he falls in love?