Cinque Izumi, Nanami Takatsuki, and Rebecca Anderson must once again set off for the continent of Flonyard to take part in the friendly war games of the three allied nations: the Biscotti Republic, Galette, and Pastillage. Cinque serves as Biscotti’s hero and is also the cousin of Galette’s hero, Nanami. Rebecca is Pastillage’s hero and a close friend of Cinque. Dog Days'' starts in the human world. Rebecca packs her belongings for the trip back to Pastillage from Japan. At the same time, Cinque and Nanami depart from England to travel to Biscotti and Galette, respectively, when a bizarre streak of bad luck—manifesting as lightning, naturally—blows them off course. They soon end up in the vast Dragon Forest, which is guarded by a Dragon Priestess named Sharu. The Dragon Priestess warns them that demons are threatening to invade the forest, as well as the entire continent of Flonyard! It appears that a genuine war is about to erupt in Dog Days''. Can these three heroes rescue the whole continent from these malevolent beings?