A noble spirit possesses the people of Springfield as they prepare for the town's bicentennial celebration. Always the iconoclast, Lisa discovers some new data about Jebediah Springfield, the town's legendary founder, that she feels she must share with everyone. According to Lisa's research, the saintly Jebediah was actually Hans Sprungfeld, a murderous pirate who tried to kill George Washington. Lisa confronts Hollis Hurlbut, the President of the Springfield Historical Society, with her findings, but Hurlbut sends her packing and bans her from his museum for three months. Lisa, with Homer's help, convinces Mayor Quimby to dig up the body of Jebediah Springfield to prove that he's not the same man as Sprungfeld. Quimby agrees, but when the body is exhumed, Hollis Hurlbut quickly steals the evidence so that no one believes Lisa. Later, Lisa finds out for sure that Hurlbut hid the evidence, but she allows the people of Springfield to go on celebrating Jebediah anyway, since the great man's legacy is more important than the actual facts of his life.