During the 2000s, humanity lost its essential life force known as purana, leading to the species' imminent demise. However, a vampire named Duo defies the norm and reveals the secret of purana, saving humans from extinction. Despite his heroic act, Duo meets the same fate as a mythical god punished for sharing fire with humans - he is doomed to face eternal punishment at the hands of fellow vampire Zieg, his once trusted friend.