This film is a campus mystery drama set in the "Classics Club" of Kamiki High School, and revolves around four members, Oreki Houtarou, Chitanda Airu, Fukube Satoshi, and Ihara Mayaka. Oreki Houtarou, a freshman at Kamiki High School, is an "energy-saving" person. He believes in "not doing unnecessary things, and solving things that must be done as soon as possible", and lives a "gray" high school life. He does not join any clubs, but because of his sister's request, he joins the "Classics Club" that is on the verge of being disbanded. In the Classics Club, he met the curious daughter Chitanda Airu, and junior high school friends Fukube Satoshi and Ihara Mayaka also joined the Classics Club one after another. It turns out that Chitanda's long-lost uncle was the head of the Classics Club at that time, so the four began to investigate the mysterious incident of the Classics Club 45 years ago, and the biggest clue was the club magazine "Hyouka" of that year. What kind of secrets are hidden in Hyouka, and why did the head of that year drop out of school... This animation is adapted from the Classics Club series of novels by Japanese mystery writer Yonezawa Honobu.