Lee Byunghun, a.k.a L.Joe, was an ordinary English major fresh graduate before he was scouted by a secret organization to be a sniper. Due to his family background, he interited his father’s skill. He had had several missions which was held successfully because of his talent and accuracy. After five years, he became the ace of the agency’s team due to his rich experiences. But he kept the cold attitude to almost everyone due to his natural being of high awareness.

One summer, he was assigned to a special task only he could run. Along with his safe pair of hands, Yoo Changhyun, who’s better known as Ricky, he began the operation which was further called Operation 508: Tasha’s Tears Tame Neat Fish. Although being his so-called partner, Ricky had no single permission to get informations about L.Joe’s mission. His duty was only to accompany the elder and to make sure the mission was a confidential one.

Operation 508 was a mission requested by an anonymous to assassinate a former agent for a Russian intelligence service, Park Hyunjin. The former agent held a special information about Russia’s top secret files. The Russian service did not wish to risk the information to be leaked to the public although Park Hyunjin had been put in a special asylum due to his lose of sanity. They wanted the information to die along with him.

But of course, it was not that easy to assassinate a former special agent. A female, named Hong Yookyung, was assigned to be Hyunjin’s special caretaker who doubled her duty in order to make Hyunjin’s existence unrecognizeable, especially for those who had had business with the now-old man.

Never once in Hong Yookyung’s dream that she had to face the hazard of facing the infamous assassin in order to protect Park Hyunjin’s soul.