Dog Days

is a 2011 Japanese fantasy anime television series created by Masaki Tsuzuki, also known for his work as creator of Magical Girl Lyrical Nanoha and produced by Seven Arcs and Aniplex under the direction of Keizo Kusakawa. Dog Days aired 13 episodes on Tokyo MX and other channels from April 2 to June 25, 2011. A second anime season aired 13 episodes from July 7 to September 29, 2012 on Tokyo MX and other channels. A third season started airing in January 2015.

A light novel adaptation with four chapters was published by Kadokawa Shoten, and serialized in the Newtype magazine between March and July 2011 issues. Kadokawa Shoten also published a Dog Days manga illustrated by Takuya Fujima, which serialized in three different magazines from May to November 2011. Several drama CDs have also been produced, as well as a comic anthology.

Plot
Cinque Izumi is a cheerful and athletic boy who studies at Kinokawa International School in Japan, and has a normal life everyday until he suddenly got summoned to an alternate world called Flonyard. The people there look no different from humans, except for one thing; they have animal ears and tails. The one who summoned him is Millhiore, the dog-like Princess of the Biscotti Republic, who requested his assistance in their war against the forces of the feline-like Galette Lion Army.

After responding to Millhiore's plea, he receives a sacred weapon, the Palladion, and is appointed as a Hero to fight for Biscotti in a war that unlike the ones in Earth, is waged with special rules and no casualties, in a fashion similar to a sports competition with the purpose to raise funds for the Kingdoms involved, where the winner faction claims a larger sum than the losing side. After winning his first battle for Biscotti, Cinque learns that when a hero is summoned into Flonyard he becomes unable to return to his homeworld, a fact that Millhiore also was unaware of.

The scientists of Biscotti promise to Cinque to find a way for him to return home in 16 days, the remaining time until his meeting with his friend Rebecca Anderson whom he promised to spend the last three days of his Spring Break with. Until then, he decides to keep serving Millhiore as Biscotti's hero.

Official

 * Dog Days Official

Other Sources

 * Wikipedia:Dog Days
 * AnimeNewsNetwork