I saw this episode when I was about 12 years old, and it is one of the Twilight Zone episodes which has been etched in my consciousness as an almost archetypal story. Without giving the plot away, suffice it to say that the combination of a large urban department store, darkness, and a plethora of life-like manikens would be frightening even without the added twists.
When our heroine, a young female shopper, goes to look for a present for her mother and winds up on the 9th floor of an 8-story department store, the real weirdness begins.
Anne Francis is both lovely and convincingly bewildered as the eerie plot unfolds. While the episode is creepy and scary, it also has a certain humor and "humanity" which in the end relieve the tension in an entertaining and ultimately satisfying way.
This is the Twilight Zone at its very best.