Gang-in Na wakes up in the year 2024 in the middle of South Korea with no memory of where or who he is. Upon hearing a voice that sounds strangely familiar, he comes face to face with a robot named ACE (Autonomous Combat Entity), who informs him that he was once part of the Earth Federation Forces in the year 2082 and possesses a wide array of skills. Gang-in decides to join forces with ACE to recover his lost memories and adapt to life on Earth, but the two look to be in for a bumpy ride.