On the surface, Liang Song (Wang Leehom) is a taciturn and introverted man, but in fact, his true identity is a cold-blooded killer working for the gang. After each mission, Liang Song would go to Japan to live a relaxed and comfortable life for a while, where he met a woman named Yukiko (Suzuki Kyoka). Liang Song was full of affection for the beautiful and kind Yukiko. He not only took the initiative to approach Yukiko, but also invited her to his home for dinner. Gradually, Yukiko's attitude towards Liang Song also changed from vigilance to dependence. In China, the police locked on the gang where Liang Song was, and for this reason, the boss had to send a distress signal to his competitors. Liang Song became a victim in the transaction between the two gangs, and he knew nothing about it. Unable to restrain his longing for Yukiko, Liang Song thought of retiring from the golden basin. He wrote a letter to Yukiko, hoping that she would make the choice.