It is 1944, the penultimate year of World War II. John Yossarian, a 28-year-old Captain and a bombardier in the U.S. Army Air Forces, does not want to fly any more B-25 bombing missions. Based on the tiny Mediterranean island of Pianosa, he has been flying missions that target various cities in northern Italy and southern France for most of the year.

Every time Yossarian gets close to completing the total number of missions required before an airman may return home to the States, his commanding officer, Colonel Cathcart, raises the number. In July, during a raid over Avignon, Yossarian witnesses the gory mortal wounding of fellow airman Snowden aboard their damaged bomber and realizes the deadly position he is in. Not only the Germans are trying to kill him; so are his superior officers, by forcing him to fly extra missions so they will look good and get promoted.

Given occasional leave, the airmen typically go to Rome, captured in early June, for rest and relaxation in a popular brothel. But as time goes by, more men around Yossarian disappear or die violent deaths.

Yossarian tries everything he can think of to get out of flying. He pretends to be very sick and hides in the base hospital. He moves the battle lines on tactical maps so they indicate the cities that his squadron is supposed to bomb have already been captured. He refuses to wear his uniform any more, walking around the base in the nude. He acts insubordinate and even crazy in hopes of being declared unfit to fly. Unfortunately Catch-22, the unwritten rule of Army bureaucracy, ensures he will never be able to get out of doing his so-called duty.

Yossarian’s colleagues react to his behavior, and to the general situation, in different ways. Major Major perpetually ducks his responsibilities, and the bureaucracy rewards him for it. Mess officer Milo Minderbender becomes a manic capitalist wheeler-dealer, buying and selling goods all over the Mediterranean theater, and even contracting with the Germans to bomb the squadron’s own base.

A pilot named Orr unaccountably keeps crashing his bombers in the ocean. Another pilot, McWatt, gets his jollies out of buzzing the other men at the base until a propeller on his plane accidentally chops an underaged serviceman in half. McWatt commits suicide by flying his plane into a mountain.

Doc Daneeka wants only to get through the war alive, but following a government mix-up he is declared officially dead so no one believes he exists any more. Captain Flume hides in the woods and cadges food from Milo. Chaplain Tappmann, shy and compassionate, gets victimized by the system: interrogated and found guilty of unspecified crimes by military investigators, he is left hanging in a legal limbo.

By the story’s end, with the help of clues left by one of his fellow airmen, Yossarian thinks he sees a way out of the insane world that has entrapped him.