Rod Serling's narration is notable in this episode because, in addition to opening and closing the show as usual, it also occurs in the middle of the story, to describe how the children spent years happily with their android grandmother and eventually grow up. Other episodes to feature mid-show narration from Serling are all from the first half of season 1: "Walking Distance", "Time Enough At Last", and "I Shot an Arrow into the Air".
The widowed father of three children takes the children to a factory, Facsimile Ltd., to pick out a new robotic grandmother. When she arrives, young Tom and Karen are quickly smitten by the magical "grandmother." But older daughter Anne is initially reluctant; "Grandma" reminds her too much of her own mother, who died and left her a bitter young girl. Anne tries to run away, and accidentally runs in front of an oncoming van. Grandma throws herself in front of the van and is struck, saving the girl. Anne grows to love her when she realizes that Grandma is indestructible and will not leave them like their own mother had.
The children grow up and are ready for college, however it's time for "grandmother" to move on to another family as she is apparently not needed anymore. The grandmother expresses her sadness to leave, yet reassures the children that they brought her just as much joy as she brought them, and that, with time, and if she keeps being a good grandmother to other children, she will even be ultimately rewarded with the gift of life and humanity. The children say their farewells and "grandmother" leaves the house for good.
This is one of the few episodes of the series where Serling does not mention the name of the show in the closing narration.