After a prank phone call to Australia goes awry, Bart and his entire family must fly out to the land down under and apologize to the Australian people. Once there, Evan Conover, the Undersecretary of State for International Protocol, Brat and Punk Division, tells the Simpsons that in Australia, the only acceptable apology is for the guilty party to receive a swift kick in the pants from the Prime Minister. Appalled by such savagery, Homer refuses to allow the Australians to "boot" his son, further fraying already tenuous Australio-American relations. Trapped in the American embassy, surrounded on all sides by enraged Australians polishing their booting boots, Bart decides to accept his punishment the only way he knows how: He pulls down his pants and moons the Australians with the words "Don't Tread on Me" written on his butt. The Simpsons escape the embassy with the Australians in hot pursuit and make it back to America, where freedom to pull pranks is a Constitutional right.
