Kwon Dohoon is an expert sniper and a secret agent working for the National Intelligence Service. To conceal his true identity, he lives a double life as a regular trading company employee, keeping even his wife Kang Yoora in the dark. Though he is occupied with his work, Dohoon cherishes his wife deeply. Meanwhile, Yoora, a dedicated homemaker, harbors a secret. Their tranquil existence is thrown into turmoil when Jo Taegoo emerges, posing a threat to their carefully crafted façade.