Take from the New Twilight Zone 1985.
The main idea for this film, two people being linked telepathically and able to see, hear and talk to each other was taken form an episode of The New Twilight Zone 1985. It was entitled "Message From Charity" Joss Whedon would have been 21 when it was shown on CBS. It was based on a short story by William M. Lee.
I only point this out because I see many comments about this being a original idea from Mr. Whedon. Also it was one of my favorite episodes of the new TZ.
https://www.youtube.com/watch?v=6XaI4UhgM8k