William Godwin writes Fleetwood largely in response to Jean-Jacques Rousseau's On Education, the premise of which is that children are inherently virtuous. Rousseau's protagonist, Emile, is brought up in nature, with no formal social or academic education. In Rousseau's version this works out well for Emile, but Godwin writes Fleetwood about a protagonist of the same name who provides a stark counterpart to Emile. For Fleetwood, his rugged and untamed childhood education in the wilderness of northern Wales proves his undoing. He's been spoiled and arrives at adulthood unprepared for social success.
Casimir Fleetwood loses his father and inherits his estate during his "grand tour," a season of traveling to mark his entry into adulthood. Receiving support from his dad's old friend, Monsier Ruffigny, whom some theorize to be an allusion to Rousseau himself, Fleetwood spends his early adult life relatively isolated. When he's 45-years-old, he marries a much younger woman named Mary Macneil. Their marriage struggles, so Fleetwood invites his cousins Kenrick and Gifford to move in with them.
In a series of manipulations, Gifford convinces Fleetwood that Mary and Kenrick have been having an affair and that her baby actually belongs to Kenrick. Fleetwood divorces his wife and moves to France. On his journey there the deception is revealed. Unwilling to continue his marriage, Fleetwood writes a will which leaves his estate to Mary, the baby, and Kenrick. He then lives modestly and alone in the Pyrenees, longing for a return to nature. Kenrick and Louisa get married. Meanwhile Gifford is executed for highway robbery.
As a commentary upon Rousseau's theories on education, this book serves to raise certain concerns regarding social adaptation for a child raised entirely in nature. Although Fleetwood adores his childhood, he is not prepared for the challenges of adult life. He has been spoiled by his rich father, never learning to work hard or to suffer humiliation. When he gets married, he falsely imagines how the relationship will play out, not recognizing the amount of sacrifice which such a union requires. He has no hard feelings for Mary, but he doesn't trust people. He's grown up largely on his own, so people are somewhat mysterious to him. By the time he learns of Gifford's monumental betrayal, Fleetwood has abandoned all desire to participate in society and retires to the mountains.
