Lt. Friday (Jack Webb) and Sgt. Smith (Ben Alexander) investigate the disappearance of a Mrs. Muller. It seems that just before the woman vanished, paroled murderess Annie Joplyn (Jeanette Nolan) was released in Mrs. Muller's custody. Contrary to her reputation, Annie is eager to help the detectives in their investigation--a bit too eager, as far as Friday is concerned! This episode is based on "The Big Thank You", the Dragnet radio broadcast of March 9, 1950. ~ Hal Erickson, Rovi