Takeru Yagi lives a normal, average life. He lives with his adoptive father Rokunosuke, and eats breakfast with two girls from the neighborhood, the sisters Asuka and Kotono. Takeru attends a kendo club at school with his best friend and rival Takeshi, and then there's Seri, an old friend of Takeru's, just returned from America. It's an idyllic, peaceful life, where the greatest drama is whether it will be Takeru or Takeshi that will represent the school at the kendo tournament. Then one day, everything changes. In an instant, Takeru and his friends are transported to a world like their own, yet fallen to ruin and filled with monsters. Moreover, people in strange clothes are highly interested in all of them, and seem to be aware they're from another world. What special destiny awaits them?

[Source: Crunchyroll]