Jun Oh, a man suffering from severe headaches. With his headaches come some unexpected special powers. Meanwhile, two narcotics detectives stumble upon a corpse under a bridge. And that's when things start to get strange...

Jun-oh, an insurance claims agent, faces off with a client who he suspects of committing murders with the intention of collecting insurance premiums.

Ahn Soo-ji and Lee Jae-joon, who are oblivious to each other's real profession as secret agents, are in an ill-fated relationship. Three years later, they accidentally meet targeting the same enemy.