Joe Schofield, a nineteen-year-old American photographer, photographs an unidentified Chinese man standing before an imposing line of tanks during the Tiananmen Square demonstrations in 1989. Joe hides the photographs just as the Chinese police break into his hotel room, beat him up, and destroy his camera.
Twenty-three years later, Joe boards a flight to Beijing with his friend and colleague, Mel Stanwyck. Sitting beside them is Tessa Kendrick, an English market research analyst on a business trip to research Chinese consumer markets. Joe is excited to see his longtime friend, Zhang Lin, an English teacher and Beijing native. Tess is nervous about flying, and Joe holds her hand.
After touring an exploitative plastics factory in Beijing run by Zhang Lin's brother, Zhang Wei, Joe meets up with Zhang Lin. Expressing his unending curiosity about the Tank Man's identity, Joe tries to photograph the hotel where he took the iconic photo but is blocked by a government agent. Zhang Lin takes Joe to his apartment, where they drink beer and chat.
Joe vows to pursue a follow-up story with Tank Man and seeks help from Zhang Lin, who has not recovered from depression since he lost his wife in the protests. Zhang Lin, who understands censorship laws better and doesn't see the protests as the acts of just one person, discourages Joe. However, Zhang Lin suggests that an immigrant to New York, Wang Penfei, might know something about the historical event.
Back in New York, Joe's editor, Frank, refuses to run the story unless it has a strongly pro-American angle. Frank's secretary, Doreen, confirms that the Tank Man is dead, effectively ending the investigation. However, Joe refuses to believe this and meets with Paul Kramer, a former reporter who wrote about the Tank Man in 1989 and more recently reported his death. Paul explains that the article about Tank Man's death, though published under his name, was written by someone else and is likely unreliable.
Meanwhile, Joe and Mel report on the 2012 presidential election, covering the debates between President Barack Obama and Senator Mitt Romney. Mel and Joe drink at a bar full of politicians and engage in a friendly, informal conversation with Senator Maria Dubiecki, slated for President Obama's cabinet.
Though still opposed to running Joe's story, Frank gives Joe a tip; Mary Chang, a Chinese immigrant who works at a strip club, was fired from her newspaper job after accidentally publishing a memorial for the "Unknown Hero" of the "64 Incident." Joe meets with Mary, who leads him to Feng Meihui, a fish stall owner and smuggler who paid for the advertisement in honor of her infant son, who was killed by a stray bullet. Meihui directs Joe to Jimmy Wang, aka Wang Pengsi, a flower shop owner who Meihui smuggled out of China in 1989.
Pengsi refuses to talk to Joe, putting a halt to his investigation. Joe and Tess meet for a business dinner, which Joe thinks is a date. Disappointed and offended when Tess asks to use one of Joe's photos for a credit card campaign, Joe rudely leaves the restaurant. Later, he apologizes to Tess, and the two become friends.
Back in Beijing, Zhang Lin suffers from depression as he sees the ghostly figure of his wife, Liuli, and listens to his elderly neighbor, Ming Xiaoli, die of a respiratory illness brought on by smog. Zhang Lin processes his feelings by recording his memories on his laptop. Zhang Lin grows increasingly angry as his brother, Zhang Wei, gives up his political idealism to pursue financial wealth and comfort.
After Ming Xiaoli's death, Zhang Lin reaches his breaking point and publishes an article criticizing the Party's lack of strict air quality regulations and inaccurate reporting. Zhang Lin assumes Joe will help him and help his nephew, Benny, but Joe is too caught up with his reporting on Tank Man and his blossoming romance with Tess to help Zhang Lin. Zhang Lin is consequently arrested and tortured.
Frank instructs Joe to drop the Tank Man story, as the newspaper's parent company wants to expand to the Chinese market. Feeling backed into a corner and censored, Joe's investigation becomes increasingly unethical. He blackmails Senator Maria Dubiecki into giving him Jimmy Wang's address and then confronts Jimmy Wang (Wang Pengsi), growing violent when Pengsi refuses to cooperate. Wang Pengsi eventually reveals that the "Unknown Hero," his brother, Wang Pengfei, was not the Tank Man, but rather, the soldier driving the tank. Joe does not understand Pengsi's perspective that Pengfei is a hero for refusing to run down a civilian, though it led to his execution. Joe is arrested for attacking Pengsi, is fired, and misses his dinner with Tess and Benny, ruining his relationships with Tess and Zhang Lin.
Months later, Zhang Lin organizes a protest in the park, causing him and Zhang Wei to be social pariahs targeted by the government. Zhang Wei moves to America, where Tess, six months pregnant and having learned more about China, participates in anti-capitalist protests. She meets up with Joe, whose protest photos are displayed in a gallery sponsored by American Express. Though Joe and Tess are in separate romantic relationships, they admit their feelings for one another.
At the gallery show, Benny and Zhang Wei approach Joe. Zhang Wei hands Joe an iPod containing Zhang Lin's recordings and chastises Joe for failing his friend. In conversation with Benny, Joe realizes Zhang Lin is actually Tank Man and calls him. However, Zhang Lin cannot speak candidly as the police search his apartment and take him into custody. Joe listens to the recordings, which reveal how Zhang Lin carried bags of his dead wife's belongings while walking in front of the tanks. In a final moment of understanding, Zhang Lin and Joe look at each other as the play ends.
