After her father's death, Ha So-min receives a call in her mother Kim Mi-yang's voice. However, So-min soon realizes that the one behind the phone is Ma Seok-gu using voice technology. Searching for clues, she finds an SOS from Mi-yang and chases a mysterious woman. As secrets unravel, So-min learns that Mi-yang's voice is being exploited by a phishing ring. Consumed by grief and rage, she vows revenge, joining forces with Detective Park Jeong-hun and turning to deepfake herself for a strike.
