Old TV shows in the public domain?

[nq:1]I had an idea for a story, but it would involve using characters from old 1950s TV shows. Do they ... 70 year? Or: could I use the character names, setting and storyline but not reference the name of the show?[/nq]
The rights to everything connected to the shows almost certainly belong to someone.
Can you do something like The Incredibles, which was very close to The Fantastic Four i

[nq:1]I had an idea for a story, but it would involve using characters from old 1950s TV shows. Do they ... 70 year? Or: could I use the character names, setting and storyline but not reference the name of the show?[/nq]
I was putting together a children's TV show with a friend (you might remember this, Lois; I think you saw some of it) that was based, in large part, on the old TV series The K

[nq:2]I had an idea for a story, but it would ... and storyline but not reference the name of the show?[/nq]
[nq:1]I was putting together a children's TV show with a friend (you might remember this, Lois; I think you saw ... as a court of law would be concerned. After all, that's what they had done themselves, ripping off The Monkees.[/nq]
... and Dee Caruso and his palls ripped off "Help"

Thanks, everybody. Looks like it's back to the drawing board with this one.
I was partly inspired by the book "The Jane Eyre Affair" by Jasper Fforde. Anybody read it? It's about this mad scientist-type guy who builds a machine that can transport real people into the original manuscripts of classic Brit Lit. Obviously, the author chose works in the public domain to include in his story. Withou

Different rules apply to that stuff. It's probably nowhere near the public domain.
See 17 USC 304.
http://www4.law.cornell.edu/uscode/