Inspired by real events, combat surgeon Sergio Passaro is deployed to a remote UN position in North Korea in November 1950, He finds himself at the Chosin Reservoir, where outnumbered Marines face annihilation at the hands of thousands of Chinese soldiers. In this brutal environment, where subzero temperatures cause blood and vials of morphine to freeze solid, Passaro must treat a torrent of casualties on the frontlines without becoming one himself.