Foe, which is set in the near future in which technology has rapidly advanced, unfolds on a remote farm, where the protagonists, Junior and Henrietta (whom Junior calls "Hen" for short), live a fruitful, but quiet and isolated life.
One day, the couple is visited by a man named Terrance. He claims to be from a mysterious organization called "the OuterMore Company" and informs Junior that he is being forced to travel to space and complete some sort of long-term mission. He will be gone for three years, but Terrance doesn't clue him into the nature of the mission. When they hear this, both Junior and Hen are upset. He doesn't want to be alone for such a long time, so Terrance reveals that the company will provide a "replacement" for Junior during his absence. This "replacement" will be an android and an almost identical version of Junior in appearance and behavior.
Throughout the novel, Junior's anxiety grows as the departure date Terrance gives him draws closer. As Terrance starts to observe him more frequently so that he can create a more realistic android, he becomes increasingly suspicious of Terrance's motives. He begins to think that the android doesn't exist and Terrence will replace him. At the same time, his relationship with Hen becomes strained as they confront the looming separation and the introduction of the doppelgänger into their lives.
Unexpectedly, one day, Junior's mirror image strides into their house. Terrance introduces the man as the real Junior, who has returned from his three-year stint in space. He informs the shocked Junior readers have come to know the rest of the story that he's merely a stand-in for the real Junior. The android Junior, shaken and in disbelief, looks to Hen for support, but she remains silent.
