In the waning years of the Shilla Dynasty, the land is ravaged by chaos and violence, as demons roam freely amongst the people. Born with the ability to see ghosts, Yi Kwak (Jung Woo Sung) joins the royal squad to help battle the demons and the corrupt court. A failed coup, however, leaves all the members but Yi Kwak dead. While hiding in a shrine, he happens upon the entrance to purgatory, where souls reside for 49 days before reincarnation. There he meets So Hwa (Kim Tae Hee), a goddess who greatly resembles his deceased lover. So Hwa, who guards the gates between the mortal realm and purgatory, is thrown into danger when an army of restless spirits attempts to return to the land of the living. Yi Kwak comes to her rescue, only to discover the army is led by his former squad comrades.