The drama tells the story of the brother and sister's father, Kiji, who was killed on the job as a police officer, and soon after, they learned that the prisoner was a cadre of Japan's largest special fraud organization "Phantom Beast", and the two decided to avenge their father. The older brother Watarase Takaichi was a former police officer with a sense of justice and action, and his younger sister Watarase Yuki was an engineer at a national university and an excellent white hat hacker. The two use their respective strengths to infiltrate the organization and confront the great evil.