Elite police superintendent Wakabayashi Yu has built her career on raw drive and an unmatched arrest record, but a promotion hinges on something she lacks: social credibility. Her superior makes it clear that a married officer is viewed as more stable, so Yu grudgingly agrees to a calculated solution. She will enter a fake marriage with her longtime colleague and workplace rival, Mikoshiba. To her, he is nothing more than a competitive peer she has spent a decade butting heads with, and the arrangement seems like a straightforward transaction: live together, keep up appearances, and secure the next rank.

That understanding shatters on the first night of their shared life. As soon as they are alone, Mikoshiba drops the act. He confesses that he has been in love with Yu for ten years and immediately makes his desire physical. The cold, teasing rival she thought she knew has been nursing an intense, unrequited obsession the entire time, using their rivalry as a clumsy way to stay close. Yu is thrown into confusion, caught between professional practicality, the shock of his revelation, and a surprisingly tender side of Mikoshiba she never let herself see.

Their new married life becomes a volatile mix of domestic comedy and growing romantic tension. Yu is famously dense about romance, still nursing old wounds from a past relationship, while Mikoshiba is a man who spent a decade expressing his love through competition and is now desperate to make up for lost time. Their relationship deepens through small, intimate moments and heated confrontations, but complications soon arise. Yu's first love, a senior officer named Serai, reappears, and his wife Mio begins circling the fake couple with suspicions and subtle interference. Mio harbors her own resentments and seems determined to destabilize whatever Yu and Mikoshiba are building.

As the two navigate the blurred line between pretense and genuine affection, their professional lives grow more dangerous. A series of bombings rocks Tokyo, and Mikoshiba is reassigned as the bodyguard for a powerful politician, a sensitive role he keeps secret from Yu. The secrecy creates a rift, but the danger soon becomes impossible to hide. Yu is drawn into the investigation, makes a dangerous infiltration, and the case escalates into a direct threat on both their lives. In the climax, Mikoshiba is caught in a broadcast bombing and left critically injured.

Faced with the possibility of losing him, Yu finally confronts her own heart. She reads a letter he left behind and realizes the depth of his ten-year commitment. After he recovers, she makes a bold decision to transfer into the security detail herself, determined to stand beside him as both partner and protector. What began as a cold calculation evolves into a bond forged through danger, jealousy, and the quiet discovery that the person who challenged her most had also been loving her all along.