Yoo Ji-an, codename “Saber,” is an S-rank government assassin who has completed over 300 missions. After 20 years in the business, he finally retires to pursue a peaceful life.

His first goal is simple: make money legally without killing anyone.

But just as he begins his ordinary new life, mysterious incidents and a suspicious woman keep getting in his way.

Can the legendary S-rank killer finally find happiness without returning to his old ways?