"Two and Two Make Four" is an Escape episode about the Channel Tunnel back when it was still just an idea. The story was fanciful at the time that it aired in 1954, but the tunnel connecting England and France became a reality in 1994. This episode appears to be loosely based on an actual tunnel proprosal that was given to Napolean III in 1856.
When he meets a young American tourist on the road, he questions her. When she tells him that he is in England, he doesn't believe her. How could she be telling the truth? He was just in Calais!
Slowly, David does begin to accept that he is in England, but he doesn't understand how that is possible. A local eccentric then explains to David that he must have come through by the way of the tunnel...the secret one that no one knows about.
"Two and Two Make Four" was written by three-time Academy Award nominated screenwriter Walter Brown Newman. David Friedkin and Morton Fine produced and directed. Featured in the cast were Shep Menken, Joyce McClusky, Tudor Owen, and Richard Peel. This episode aired on August 21, 1954.
(Image from Wikimedia Commons)