The Valkyrie Sigrun marries a mortal out of gratitude, believing he's the one who saved her, only to be betrayed by him. After leaving the mortal, she hastily weds a crippled outcast—only to discover he is the God of Light, whom she cast down to the mortal realm ten thousand years ago. Now, with Ragnarök looming, Sigrun learns the God Key—a new god born of a Valkyrie's blood—may be the only hope of saving the Nine Realms, but its power can only be awakened by her true one.
