Another ordinary day finds Houtarou Oreki at home as usual, until his sister Tomoe convinces him to work as a lifeguard at the nearby swimming pool. Upon arrival, Oreki serendipitously reunites with the other members of the Classics Club. Eru Chitanda notes the sudden disappearance of a white object from a woman's ear, sparking her inquisitive nature and prompting her to delve deeper into the mystery. Hyouka: Motsubeki Mono wa follows Oreki and his friends from the Classics Club as they enjoy themselves at the pool while unraveling the enigma that has captured Chitanda's attention.