A "VIP of the Underworld" whose specialty is dying young. "Ah, I died again..." Sangra Heeyo, the Heavenly Princess, is the deeply cherished only daughter of the Jade Emperor and the King of the Underworld. The only thing she lacks is a healthy body. After hearing the tragic story of a young mortal princess named Seruha in the Underworld, Heeyo decides to break the rules. Since Seruha has lost the will to live, Heeyo secretly runs away to the human realm to take her place, sneaking past her parents. "Wait, why are there so many humans trying to kill a little kid?!" She wakes up in the Empire of Un, married off like property. Not only is the place crawling with enemies trying to kill Seruha, but there are also assassins targeting her new husband, Crown Prince Cheon Gyeol-woo. "I can't just stand by and watch these villains bully innocent people!"