Four assassins with extraordinary skills hide in the streets of the United States under an assumed name. They were once carefully trained pawns by the National Security Agency, but they were controlled and banned by the Security Agency because they were too reckless in their missions and caused unnecessary harm. One day, the appearance of a beautiful woman named Mei Mei (played by Su Jin) brought the four people together again. Mei Mei hired them to assassinate her sister Mei Li (played by Su Jin) just because Mei Li killed their parents and occupied the family's huge industry. There are four killers, but only one person is enough to complete this task, so a thrilling fight unfolds between the four. In the end, the scholar became the final winner, but he found that he actually fell in love with the seemingly fragile Mei Li. At the same time, the scholar also found that the facts did not seem to be as Mei Mei described.