In a near‑future Japan, authorities have launched an elaborate program known as "The Crimson Threads of Science" to promote successful unions and curb the nation"s falling birthrate. The state calculates compatibility scores for sixteen‑year‑olds, then designates their future spouses; those who deviate face harsh penalties. For the otherwise ordinary Yukari Nejima, this scheme offers a possible path to a meaningful life.
Yet his long‑held affection for classmate Misaki Takasaki drives him to rebel against the mandate and declare his love. Though hesitant at first, Misaki responds with equal passion. Just as their romance seems to take shape, Yukari is summoned to receive his official marriage summons. He then finds himself entangled in a tangled maze of desire and deception when the disinterested partner assigned to him, Ririna Sanada, becomes intrigued by his forbidden liaison.
