A gentle and dignified girl promised a engagement with a handsome prince for the glory of her family.However, she gradually discovered that the true purpose of the royal family marrying her was to offer her as a sacrifice to a dragon sleeping in ancient legends - this was the price of the royal family's blood debt owed by their ancestors a hundred years ago. When she was pushed into the dark cave, flames gushed and huge shadows entrenched, fear almost swallowed her.But she did not despair, but held the only remaining courage and wisdom, looking for vitality in the shadow of death.In this struggle against the behemoth, fate and betrayal, she must awaken the most tenacious force in her heart in order to survive in desperate situations and even rewrite her own destiny.