Gloria is a typical eight-year old in every way, with one exception: her nanny is a robot named Robbie. Robbie is programmed and designed to be the perfect companion for a child and to protect her at the cost of his own life. Gloria and Robbie spend their days playing hide-and-seek and sky pirates in the yard. Robbie loves hearing stories told by Gloria, and his favorite one is Cinderella.
Robbie is afraid of Gloria’s mother, and for good reason. Every time Gloria misbehaves, her mother threatens to send Robbie away. One day, Gloria’s mother has enough and tells her husband that she doesn’t want her daughter unnaturally attached to a machine. Gloria’s father insists that Robbie is the best thing that could have happened to their family. Over time, though, Gloria’s mother wears him down. The townspeople are afraid of Robbie and won’t let their children near the house at night, and the people of New York City stop allowing robots on the street after dark. Finally, Gloria’s father agrees to sell Robbie back to his company.
Gloria’s father surprises her with a trip to the movies. Gloria wants to take Robbie, but Gloria’s father tells her that Robbie isn’t allowed in the theater. When they return, Gloria can’t wait to tell Robbie all about the movie, but Robbie isn’t there. Instead, there is a big dog waiting for Gloria, and her mother tells her that Robbie just walked off and disappeared.
Despite her mother’s assurances, Gloria does not feel better over time. Instead, she sinks into a deep depression and loses weight. Gloria’s mother has to give the dog away, because Gloria refuses to play with it.
To distract Gloria form Robbie’s absence, Gloria’s mother suggests a month-long stay in New York.
Gloria’s mood improves, and she grows more and more excited every day. On the plane to New York, Gloria tells her mother she knows they are going to look for Robbie.
The family does all the normal tourist things in New York, but it is no use. Everywhere they go, Gloria looks for robots. At the Museum of Science and Industry, Gloria runs away from her parents to ask the Talking Robot if he has seen Robbie. The Talking Robot is not programmed to answer such questions, and his circuits fry. Gloria is despondent.
Gloria’s father suggests a trip to a factory where robots are made to show Gloria they are not humans, but machines. Gloria’s mother agrees, ready to try anything. They take the standard tour, and then Gloria’s father suggests a visit to the room where robots are employed in making other robots. Gloria quickly recognizes Robbie on the assembly line. She scoots through the guardrail and runs to Robbie, while an oncoming tractor is headed in her direction too quickly to stop. Robbie grabs Gloria and pushes her to safety, seconds before death.
Gloria’s mother realizes the reunion was pre-arranged, but she can’t be angry because Robbie saved her daughter’s life. She grudgingly tells Gloria that Robbie is welcome to live with them for the rest of their lives.