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.