Cinque returns to the land of Flonyard in Dog Days' to resume his duties as the hero of the Biscotti Republic and it's as though he never left! The difference this time is that he's brought two friends with him who become heroes in their own right: childhood best friend Rebecca Anderson, who becomes the hero for the Principality of Pastillage at the urging of their leader Princess Couvert Eschenbach Pastillage, and his cousin Nanami Takatsuki, who becomes the hero for the Galette Lion Dominion. As with the first season though, with so many secrets to be uncovered and mysteries to be solved, will there even be time for the athletic events that these three hyper and athletic teenagers love to participate in so much?

Dog Days takes place in the world of Flonyard, an alternate Earth inhabited by beings who resemble humans, but also have the ears and tails of specific animals. The Republic of Biscotti, a union of dog-like citizens, has come under attack by the feline forces of the Galette Leo Knights. In an effort to save Biscotti, Princess Millhiore summons a champion from another world in order to defend her people. That champion is Cinque Izumi, a normal junior high student from Earth. Agreeing to assist Biscotti, Cinque retrieves a sacred weapon called the Palladion and prepares for war. In Flonyard, wars are fought with no casualties and are more akin to sports competitions with the goal of raising money for the participating kingdoms. Cinque is successful in his role as Biscotti’s champion, but learns that a summoned champion cannot be returned to their home world. The scientists of Biscotti will endeavor to find a way for Cinque to return home, but until they figure something out, he must serve Princess Millhiore by continuing to fight as Biscotti’s hero.

Inaba Yuushi's parents died in his first year of middle school, and he moved in with his relatives. Though they did care for him, he could tell he was a burden. After he graduated, he happily prepared to move to a high school with a dormitory. Unfortunately, the dormitory burned to the ground before he could move in! Yuushi doesn't want to live with his grudging relatives, but it's rough finding lodging as an orphaned student with little money. He finally finds a room in a nice old building which seems too good to be true. The catch is that it is a Monster House, a place where humans and supernatural creatures—ghosts, mononoke, etc.—live together. Another high schooler lives there, a cute girl named Akine, and she's completely unfazed by the monsters. In fact, she can even exorcise evil spirits! Yuushi's high school life just got much stranger than he ever bargained for! (Source: MangaHelpers)

Severe internet addiction has become an epidemic infecting the nation's youth, ultimately resulting in their extreme dependence on the world wide web. Those who are too far gone are enrolled at Elite Reeducation Academy in order to help them grow into successful adults. Hibiki is one such teenager who awakens in the facility unaware of how he came to be there. He learns from the head instructor that he was knocked out and brought to the school at his mother's behest, concerned with how belligerent her son was becoming as a result of his internet addiction. Stuck in a place more akin to a prison than an academy, and with no escape from the abuses of the instructors, Hibiki decides to end his life by jumping from the roof. But as fate would have it, he meets a mysterious man named Shin who promises to give his life meaning... [Written by MAL Rewrite]