The Twilight Zone - Season 3 Episode 1

A woman tries to get her Uncle Edgar committed, believing that he is senile. The investigating doctor finds Edgar living in an apartment containing all kinds of junk. Edgar claims that a mysterious Voice tells him what junk to collect, and to assemble it into a device that constantly keeps the world in balance. The doctor has him committed, only to realize when a small Pacific island is destroyed as Edgar predicted that the "insane" man is anything but. The doctor has Edgar released, only to discover that he has been chosen to replace Edgar as the new "balancer" of the world.