An old man saves an injured snake spirit, but it attacks him after recovery! His daughter-in-law arrives, and the snake spirit stops its attack. It then takes the daughter-in-law hostage, forcing the old man to the Back Mountain Cave. They head into the mountains, fighting evil pythons, uncovering past truths. The snake spirit realizes its mistake, returns to the mountains with its young. Is it betrayal or a hidden reason? The truth is unexpected!