Set during the beginning of World War II, the narrative of A Separate Peace finds the seniors at the age of the draft. That is, they can be called to duty by the United States Government and required to be in the Armed Services and fight in this war.
In contrast to this war, Devon School offers Gene and Finny and the younger boys the opportunity to revel in the careless peace of their environment. And, yet, Gene eventually finds "something deadly" in these surroundings, waging his own war against himself and Finny. Thus, the setting of World War II parallels much of the interior action of Knowles's novel. In Chapter 7, for instance, Gene considers enlisting,
To enlist. To slam the door impulsively on the past, to shed everthing down to my last bit of clothing, to break the pattern of my life--I yearned to take giant military shears to it, snap!
In the end, after having served in the war, Gene realizes that he has fought his greatest battle and injured others most in his private war at Devon.