Princess Era of the White-Gray Kingdom once, to save Prince Kaelen, cut open her own heart to give him half of it; her stepsister Seraphina stole the credit and long bullied and framed her. On the day of the sacrificial wedding, Era is pushed into the abyss by her own father and fiancé, and meets Valso, the cursed blind Dragon Lord of the abyss. Drawn by Era's pure bloodline, Valso protects her all the way, and through trials the two bind their bond with a dragon-scale contract. Kaelen finally awakens and chases after her in regret, but loses Era for good because of his past sins. Era joins Valso to settle all the wrongdoers, end the hypocritical monarchy, and build an equal, co-governed abyss kingdom—upholding the positive belief that good and evil are repaid and only true hearts can stay together.