Dana Ranson has disappeared. I fell into the floor right at school. Everything that happened seems like a nightmare until Owen, John and Sydney discover that Hades himself, the Greek god of the kingdom of the dead, kidnapped her. To rescue their friend, the friends go on a dangerous journey through the afterlife of the ancients: Greek, Egyptian, Scandinavian. But no one suspects that the ordinary girl Dana is just a puppet in the hands of the cunning and cruel northern god Loki, who unleashed monsters on the earth. The battle between gods and mortals begins...