In this early episode, Mister Rogers shows how locks and keys work both at his place and at Bob Trow’s workshop.In Make-Believe, King Friday plans to welcome Collette by giving her a “Key to the Kingdom.”But Henrietta, who is jealous of Collette, is afraid Collette’s key will unlock her house and she wants her privacy. Lady Aberlin assures her that of course the key will not open Henrietta’s door, that she misunderstood. The “Key to the Kingdom” is just a way to say “Welcome.”