The exhausted warrior Munsu, lost and unable to continue his journey in the desert after wandering for days, is luckily rescued by Mon-ryon, a young man with aspirations of becoming a spy for the ancient empire of Jushin, which was destroyed not long ago. Mon-ryon's primary objective is to save his loved one, Chunhyan, who is currently held captive by the villainous Lord Byonand. However, their hopes are quickly crushed when the cannibalistic Sarinjas fatally wound Mon-ryon. Using his intelligence to convince them to spare his life, Munsu decides to complete Mon-ryon's mission, cautiously agreeing with his intentions. With an army of ghosts summoned by Angyo Onshi, Munsu successfully liberates Chunhyan. While visiting Mon-ryon's grave, Chunhyan promises to protect Munsu's back and they set out to avenge Jushin's former glory.