I remember this guy (who was kind of the focus of the episode) whose dad had been accused of killing his childhood friend (a young girl). She had been missing for years and because no body was found, the boys dad had been dropped of all charges from lack of evidence but the boy was certain his dad had done it because he remembered him coming in with muddy shoes the night she went missing. Years later, the man never forgave his father. He found out his father was ill and his sister tried to convince him he needed to forgive their father. I believe as the dad is dying he says “shes under___” (something I cant remember). It makes the guy think shes burried under his old playhouse in the back yard of their childhood home. Him and his sister go digging for her. They find nothing and the sister says their dad was just crazy. Then the boy remembers a campsite they used to visit and rushed over there only to find her body still in her rain boots from the night she was murdered
That sounds like one of the plotlines from the first season of Blindspot
https://www.imdb.com/title/tt4474344/