A young 18-year-old boy named Ryoshi Tanaka, is good at kendo and judo. Also, he is smart. One day after school and practicing in dojo, he go to his sensei's mini library, and saw a blank book titled, "Welcome to another world.". When Ryoshi opened the book, suddenly he's been sucked into the book. "Where am I?" , he saw an old buildings and he's confused. What will Ryoshi Tanaka do?