Dimension X: Knock (Dramatized‪)‬

"The last man on Earth sat alone in a room. There was a knock on the door...." Based on a story by Frederic Brown, this episode of Dimension X originally aired May 6, 1950.
Featuring "adventures in time and space told in future tense", Dimension X aired over NBC from April 8, 1950, through September 29, 1951. The series adapted stories by the modern masters of science fiction, including Ray Bradbury, Robert Heinlein, Clifford Simak, Theodore Sturgeon, and many others.