Kosta and Anna Alexopoulos have brought their adopted son Adonis to England where they now run a small Greek restaurant, preserving what they can of their cultural past. Or at least what they think was their past. The years have passed quickly for the Alexopouloses and Adonis is grown up, yet they still have not told him that he is adopted. The central conflict lies with Kosta, who does not feel like a real father to Adonis, and believes that Adonis is reciprocating by not being a real son.
The story begins with a common image for Swift, an atrocity of World War II. Kosta begins by telling us that he once "cut the fingers off my own mother" (p.124) to avoid starvation during the German occupation of Athens. This violence is part of the unhappiness and trauma that Swift seems to feel is a prerequisite for one of his characters.
Kosta fears the past more than anything, for it is the past that will reveal the truth to his son. When Adonis begins to frequent a club popular with Greek immigrants Kosta asks him, "What do you want with all those old madmen?" (p.131) and puts down their stories as nonsense. This is an out and out rejection of the folk tales which make up history, a concept which is of vital importance in Swift's later novel, Waterland. There are in fact many elements of "The Son" which become important building blocks not only of Waterland but also of Out of This World.
Adonis finally travels back to Greece where he finds several people who remember the war and can tell him the truth about his parentage. Upon his return to London he tells Kosta that not only has he found out that he was adopted, but that Kosta was adopted as well. His real name is not Alexopoulos, for his parents were killed by the Turks, and he was adopted by his neighbors. "Tell me, who are we?" asks Kosta, "What's important, what isn't? Is it better to live in ignorance?" (p.135) Not only is the invisible seemingly tragic but it is too much for Kosta to bear. The whole concept of a hidden past being the same thing as no past at all is another of Swift's familiar themes. For his characters, it is often better not to know.