Jeong Taeui has always lived in the shadow of his genius twin brother, but he's never been unhappy with his ordinary life. When his uncle shows up at his doorstep with a dangerous job offer disguised as a once-in-a-lifetime opportunity, Taeui is skeptical, but he reluctantly agrees to work as an agent for half a year. Despite his initial qualms, he quickly adjusts to his new environment using his outgoing, positive personality. But from the moment Taeui meets Ilay Riegrow, an agent from another branch, his peaceful life slowly starts to change. Everyone says Ilay is a sadistic psychopath who should be avoided at all costs, but Taeui knows there's more to him than meets the eye. But getting to know Ilay is like playing with fire, and Taeui isn't sure if he's ready to get burned.