Nonton Once in a Summer (Geuhae yeoreum) (2006) Sub Indo

An assistant to a TV producer, eager to stay off his bad side, promises to convince her former professor, a famous but reclusive academic, to appear on their show, which helps locate long-lost persons. Who does grey-haired Professor Yun Suk-Young want to see again more than anything? The answer to that question lies decades in the past.