가급적 에너지를 최소한 쓰면서 살아가자는 주의를 가진 호타로가 난데없이 고등학교 고전부에 들어가게 되고, 지역 유지 집안의 아가씨인 에루와 함께 이런저런 사건들을 풀어가게 된다. 일단은 10년 전 사라진 숙부와 얽힌 사건부터. 유명한 라이트노벨과 애니메이션이 원작인 영화.

Energy-conservative high school student Houtarou Oreki ends up with more than he bargained for when he signs up for the Classics Club at his sister's behestespecially when he realizes how deep-rooted the club's history really is. Begrudgingly, Oreki is dragged into an investigation concerning the 45-year-old mystery that surrounds the club room. Accompanied by his fellow club members, the knowledgeable Satoshi Fukube, the stern but benign Mayaka Ibara, and the ever-curious Eru Chitanda, Oreki must combat deadlines and lack of information with resourcefulness and hidden talent, in order to not only find the truth buried beneath the dust of works created years before them, but of other small side cases as well.