Yane no Shita no Artemis

A prodigy of science and a solitary genius—yet terrible at so many things!? Poor university student Sanosuke Saraki unexpectedly reunites with his admired genius classmate, Koharu Kobachi, at his part-time job back at his old school. However, this supposed genius is now a "5th year high school student" who has repeated her second year in a row...! Saraki's mission is to "make Koharu graduate by the end of the year." A coming-of-age story about starting over with a 20-year-old high school student under the same roof!