On January 1, right after New Year's Eve, Ned Flanders completes his yearly taxes.
Later that year, just before midnight on April 15, Homer realizes he did not file his tax return. He rushes and provides false information before driving to the post office. When the tax returns are sent to the IRS, Homer's oddly-packaged return fatefully bounces into the "Severe Audit" bin. The IRS discovers Homer's fraud and he is arrested. Held by the government, Homer says he will do anything to stay out of prison. Agent Johnson of the FBI decides that Homer can be useful. With a hidden microphone under his shirt, Homer uncovers that his coworker Charlie leads a group planning to assault all government officials, but is arrested by the FBI for conspiracy.
With his superiors impressed, Johnson sends Homer on a secret mission. They reveal that in 1945, President Harry S. Truman printed a one trillion-dollar bill (with his picture engraved on it) to help reconstruct post-war Europe. He handed the bill over to Montgomery Burns to transport to the Europeans, assuming that the richest man in America would be the best person to trust the bill with. However, the money never arrived and the FBI suspects Burns still has the money with him. As satellite photography can only confirm that the trillion-dollar bill is not on the roof of Burns' home, Homer is sent in to investigate. Arriving at the Burns estate, Homer searches for the money before Burns, who believes Homer is a reporter from Collier's magazine, reveals that he kept the money on his person. Johnson and Agent Miller burst in and arrest Burns for "grand-grand-grand-grand-larceny". Burns shouts how the US government oppresses the average American and tells Homer to write, "Don't let the government push you around!" in his article. Moved by Burns's speech, Homer knocks out the FBI agents and frees Burns. The two men hurry to obtain Smithers for help, who suggests they leave the country. Burns takes Smithers and Homer in his old plane, setting off to find an island and start a new country. Over the Caribbean, Burns finds a fine island, although it already has a name and is in fact the country, Cuba. Going before Fidel Castro (after learning, much to the surprise of both Burns and Simpson, that Batista is no longer leader of Cuba), Burns fails to buy the island when Fidel asks to see the trillion-dollar bill, and is handed the bill. When Burns asks for it back, Castro responds: "Give what back?" Then, the episode immediately cuts to a scene where Burns, Smithers, and Homer are on a makeshift raft. Burns announces he will merely bribe the jury when he, Smithers and Homer are put on trial, prompting Homer to exclaim "God bless America!" and salute.