Little Girl Lost is an offbeat, nicely done Twilight Zone from the show's third season. After some weak episodes, this one, written by Richard Matheson, really scores. I wouldn't call it one of the best of the series but its high in the second tier.
A young suburban couple are awakened from their sleep by the sound of their daughter's crying, but when they go to look for her she's not in her room. The family dog's bark can also be faintly heard; but he's not there, either.
A scientist friend is called and he tells them the bad news: the child and dog have slipped into another dimension. He doesn't call it the twilight zone must he may as well have, as that's what it is.
The scientist manages to find a spot in the wall behind the child's bed that appears to be a kind of hole in the wall,--only there ain't no hole, but his hand disappears into it when he touches it--and he proceeds to outline it with a piece of chalk.
In short time the father enters the twilight world into which his daughter has apparently, as the scientist puts it, "fallen into"; and the dog is there, too. It's weird and trippy looking, and it feels like a planetarium designed by a madman.
Not quite outer space, it's strange place with no boundaries. Nowadays we might call it a parallel universe. At the time the episode was made it was more like nowhere.
Kudos for the studio art department for creating this eerie and yet oddly seductive place. I'd love to have seen more of it. The child and her dog are saved, but just barely, as the hole in the wall was apparently in the process of closing up just prior to their return.
There's some food for thought in Little Girl Lost; and it's difficult not to be intrigued by its basic premise. The scientific ideas, such as they can be called, aren't all that well presented but they're good enough for a well above average half-hour of television.