In a city of the dead, long since ruined and far from human civilization, lives a single human child. His name is Will, and he's being raised by three undead: the hearty skeletal warrior, Blood; the graceful mummified priestess, Mary; and the crotchety spectral sorcerer, Gus. The three pour love into the boy, and teach him all they know. But one day, Will starts to wonder: "Who am I?"
Will must unravel the mysteries of this faraway dead man's land, and unearth the secret pasts of the undead. He must learn the love and mercy of the good gods, and the bigotry and madness of the bad. And when he knows it all, the boy will take his first step on the path to becoming a Paladin.
Thirty years ago a strange phenomenon called a "spacequake" devastated the center of Eurasia, claiming the lives of at least 150 million people. Since then, smaller spacequakes plague the world on an irregular basis. Shido Itsuka, a seemingly ordinary high schooler comes across a mysterious girl at the ground zero of a spacequake and learns she is one of the "Spirits" who are the real cause of the spacequakes that occur when they manifest themselves in the world. He is recruited to make use of his mysterious ability to seal the Spirits' powers thus stopping them from being a threat to mankind. However, there is a catch: to seal a Spirit's power, he must make her fall in love with him and kiss him.