The Metropolitan Police Department Special Unit's Ryo Kawakubo is an ace at handling dangerous cases; with his colleague, Kuroki, he is called to the Metropolitan Heliport, where they meet Song Shi-Won.

Ryo has a deep secret -- he buried his younger brother with his own hands; Shi-Won has lost all memory of the woman he loved, Kana Ayatsuji; after returning to Japan, Kana gets caught up in a street crime.

Shi-Won, who was shot in the head, is delivered to the hospital; although the surgery was successful, the surgeon discovers that someone else had performed surgery on Shi-Won's brain; mysterious enemies target Shi-Won.

Ryo is informed that Shi-Won wakes up; a surveillance camera catches an image of the criminal, but Shi-Won has no recollection of the individual; Ryo gets lost in the memories of his deceased brother, Shige.

Foreign DNA is discovered in Shi-Won's brain -- the DNA of Einstein; Honda sends a sample of Shi-Won's brain to Professor Mikoshiba, the Japanese authority on neurology; several killings happen in Tokyo.

Since joining the police force, Ryo has been constantly checking the data of "missing persons" to find his mother who had abandoned him and his younger brother; now a member of the Special Unit, Shi-won starts using his hacking skills.