Magnum, P.I. (1980)

Thomas is hired by Jack Damon, Carol's Uncle, to find his seventeen-year-old daughter Becky, who has been missing for two months, after leaving home against his wishes to pursue a career as a dancer. After a little investigating, Thomas finds that the last person known to have seen the girl was her former boyfriend Darryl Jacobs – who is now behind bars after being involved in a stolen guns deal that went bad. Magnum decides the only way to find out from Jacobs what happened to Becky is to go undercover as a convict at the prison farm where Jacobs is being detained...