In the war in the ancient times, many powerful weapons were lost and one of the most dangerous weapons of them all is Pandora's Box. The legend Pandora's box is just a lie but the truth of Pandora's Box is more deadlier than any beast in this world and the Underworld. Three Demigods have been chosen to find and destroy Pandora's Box before Persephone returns from the Underworld before Spring Arrives.
(I claim Caden to be one of the Demigods. I'm planning of making a fanfic based on this.)