Eden, Michigan, high school student Kate Winters strikes a bargain with Henry, Greek god of the underworld, if he'll cure her dying mother of cancer. The bargain she strikes with him is a grim one, but the full enormity of what she has undertaken--"live forever or die trying"--is not revealed until it's too late to recant.

About to be crowned Queen of the Underworld, the immortal Kate Winters must save Henry from the depths of Tartarus. But in order to navigate the endless caverns of the Underworld, Kate must enlist the help of the one person who is the greatest threat to her future: Henry's first wife, Persephone.