In Brooklyn in 1939, Sammy Klayman, a seventeen-year-old Jewish boy, lives with his mother and grandmother. One night, his cousin, Josef Kavalier, appears unexpectedly from Prague. Josef’s parents had spent all their money on helping their son flee the country, but when visa regulations prevented his departure, Josef conspired with his magic teacher, Kornblum, to escape another way. He was packaged into a crate with Prague’s legendary Golem and shipped out of the country.

Josef is a talented artist. Sammy introduces him to his employer, Sheldon Anapol, who says he will take them on as comic-book artists if they can make him “a Superman.” He asks for a sample comic, which they create alongside some of Sammy’s artist friends at their apartment. As an alternative to Superman, Joe and Samuel create the Escapist. It quickly becomes clear that Sammy’s real skill lies in writing, rather than drawing, and he becomes the scriptwriter.

The comic impresses Anapol, although the strongly anti-Nazi element makes him nervous. He takes the boys on, and the Escapist becomes an enormous success. However, Joe Kavalier and Sammy Clay, as they are now known, have sold the rights, so they make less money than they could have.

When Joe hears that his father has died back in Prague, he becomes more set upon saving his mother and brother. He becomes embroiled in a brief feud with Carl Ebling, the chief of the Aryan-American League. This culminates in Ebling’s trying to set a bomb at an event where Joe is performing as an illusionist. Ebling is arrested and sent to prison.

When the Escapist is taken on as a radio drama, George Deasey at Empire suggests that Sammy and Joe ask Anapol to renegotiate their contracts.

At a party at the home of art dealer Longman Harkoo, both Sammy and Joe are changed by their experiences: Sammy is shaken by the sight of two men kissing, and Joe gets together with Rosa Saks, a fellow artist. Rosa knows the owner of the Transatlantic Rescue Agency, who, in exchange for money, promises to help rescue Joe’s brother, Thomas, from German-occupied Prague.

Joe and Sammy renegotiate terms with Anapol when Deasey lets slip that Anapol is being sued by Superman’s creators. Sammy perjures himself in court, saying the Escapist is unrelated to Superman. 

As they become wealthier, Joe saves his money to eventually start a family. Meanwhile, Sammy falls in love with Tracy Bacon, the actor who voices the Escapist on the radio-drama adaptation of the comic. 

Thomas is finally on a ship to the USA, but it is sunk by a U-Boat. Joe is performing a magic act at a bar mitzvah when he receives the news, and he is devastated. At this time, Rosa is pregnant with his child, and she is unable to tell Joe about the pregnancy before he leaves to join the Navy. Meanwhile, Sammy narrowly escapes an arrest for homosexual behavior by sexually gratifying an FBI agent. He had been at a house party, where he was recognized by Ruth Ebling, the brother of Carl, who knew of the connection between his own arrest and the Escapist comics and so sought revenge on Sammy. 

Joe spends the war in Antarctica. A carbon monoxide leak kills everyone on base but Joe and his comrade Shannenhouse, who overhear German transmissions from a nearby base. En route to this base by plane, Shannenhouse dies of appendicitis. At the German base, Joe accidentally kills the German radio operator and is traumatized by the event. He has also learned through letters that Sammy and Rosa are married and that...