It tells a thriller story of a crime investigation about the friendship between friends that deteriorates as a narcotics detective is forced to investigate a high school classmate who left behind 5 billion won in insurance money after being involved in drug-related crimes because someone was forced to do so. Ji Sung plays the calm and meticulous character of the serious crime team Zhang Zaijing, who received 5 billion won in insurance money after his high school classmate chose to die. He is highly respected in the police station, and keeps a distance from friendship, work, and family, and believes that he must protect his principles. Tian Midu plays Oh Yoon-jin, the economic director of a shabby news company who returns to his hometown after being wrongfully fired. When her husband and children immigrated overseas and she sent her living expenses alone, she heard the news that her high school classmate died and left 5 billion won in insurance money, and showed the true face of friendship. He has a strong self-assertion, is brave, and is determined to become a rubbish reporter.