In 1975, Detroit, Michigan, Mort Golden, a twenty-one-year-old aspiring writer, and his friends, Danny Morgan, a former high school football star, and Tim Reese, a hot-head who is quick to fight, cruise around town in their unregistered Buick dubbed “The War Wagon,” with occasional forays across the Ambassador Bridge to visit strip clubs in Toronto, Canada. Although Mort is content, his mother wishes he would attend college and submits an application to a state college on his behalf. John Anderson, a local drug dealer, offers the three friends $9,000 to smuggle “hash” from Canada. Mort worries about getting caught, but John claims the border guards will not find drugs hidden in a spare tire. Mort, Danny, and Tim consider the offer, but do not commit. Later, Mort and Tim accompany Danny as he puts flowers on his mother’s grave. She died shortly after Danny won the state’s high school football championship and graduated. Danny’s father, Lou, the high school football coach, now spends most of his time drinking at home with his new girl friend, Faye Collins. Mort works at his Uncle Alby’s typewriter repair store, and Alby wants him to meet his friend, Manny Goldfarb, an accomplished writer who is visiting town. However, Mort has plans to go to a Toronto strip club with Danny and Tim. As they cross the bridge and contemplate smuggling drugs, Mort announces that he wants to visit his former girl friend, Carol Brockton, at the Canadian university she attends. Danny tells Mort to forget Carol, who dumped him two years ago, but Mort still loves her. Danny drops Mort and Tim at the strip club, and unexpectedly leaves to run an errand. When he returns, the club has already closed. As they near the border returning home, Danny reveals that he completed the drug deal, and has hidden the hash in the spare tire. Mort and Tim are upset and want to discard the drugs, but Danny refuses and orders them to act normal. At the checkpoint, they are asked to get out of their vehicle, and then frisked while the car is searched by a drug-sniffing dog. An officer opens the trunk and looks inside, but does not touch the spare tire. As they cross back into the U.S., Danny admits that he lied and there are no drugs in the car. He tested his friends to see if they could handle the pressure and declares they failed. He notes that the guards never checked the spare tire and insists they would have successfully smuggled the drugs. The next evening, Uncle Alby brings Manny Goldfarb to dinner at Mort’s home. As Manny regales Mort with stories of his adventures as a reporter, he has a heart attack and dies. Uncle Alby blames Mort for Manny’s death, and fires his nephew. In time, Mort is admitted to Central Michigan University, and pockets the acceptance letter without telling anyone. Mort, Danny, and Tim are invited to a dinner party of former classmate “Smiling Jack” Harper, to celebrate his promotion to an executive position at his work. Mort is excited that Carol Brockton is also a guest, but learns she is dating Randy, another former classmate who attends college with her. When Smiling Jack’s college friends make derisive comments about Danny and Tim, Mort stands up and declares that the other guests have abandoned their childhood dreams. He kisses Carol, and leaves, impressing Danny and Tim with his boldness. Sometime later, Danny’s father shares his plans to sell their home, marry his girl friend, Faye, and rent an apartment with her. Angered, Danny challenges his friends to make the drug run. Tim agrees, but Mort hesitates until Danny mentions visiting Carol in Canada. When they arrive, Carol is happy to see Mort, and he pretends to accept that they can only be friends because of her boyfriend. As the couple talks, Danny drives up and Tim grabs Mort, holding him outside the car as they drive away. They pickup a briefcase containing money for the drug deal, and afterward, Mort declares that his friends embarrassed him in front of Carol and insists on seeing her again. Under the cover of darkness, he sneaks into her dorm room. Carol asks him to leave, but Mort declares he is still in love with her and might always be. He tells her about his dream of moving to Los Angeles, California, to become a television writer. After she offers her encouragement, they make love. Mort rejoins his friends, and they drive to a remote farmhouse, where they hand the briefcase to the drug dealers. Upon seeing how much money is inside, the trio realize they will be transporting heroin, not hash. Danny protests, but Mitchell, the tough drug dealer, does not care. As Tim grabs the briefcase, the drug dealers pull out their guns. Tim insults Mitchell, and the drug dealer plans to teach him a lesson by shooting off his toe. Mort intervenes, declaring Tim will boast about losing a toe, and suggests Mitchell beat him up instead. After delivering the beating, Mitchell puts the spare tire filled with heroin in the car, and orders them to leave. At a rest stop, Tim thanks Mort for saving his toe. Danny telephones John Anderson, who promises to give them $10,000 each if they smuggle the heroin across the border, and Mort worries they will go to prison for fifty years. However, Danny wants the money, and Tim will not back down. As they wait in line on the bridge, Tim changes his mind, realizing that if they are successful, he will keep smuggling drugs until he is killed. Despite Danny’s protests, Tim exits the car and walks across the border. Mort asks Danny to stop, insisting that the car is not registered to them, so they can abandon it, but Danny refuses and tells him to leave. Mort starts to walk away, but soon returns. He is furious, but claims he does not have a choice and must stay at his friend’s side. After seeing the guards and drug-sniffing dogs searching cars ahead of them, Danny finally agrees to leave the car and walk across the bridge. They make it through customs as guards swarm the abandoned car. As they join Tim on the other side of the border, Danny admits that Mort was right. Mort chooses to walk home while Danny and Tim leave in a taxi. Six months later, Mort leaves for college, and as time passes, his friendship with Danny and Tim slowly fades.