Lisa runs into Annie in the library. Annie is doing an article for a newspaper and tells Lisa her ancestor Cordelia Heffenbacher was a traitor during The Revolutionary War. Lisa and her friends go to her mother's house to check on the family tree. Lisa's mother tells her that Cordelia made doughnuts for the British redcoats. Lisa wants to prove her ancestor wasn't a traitor. She visits her aunt's house in which Cordelia used to live. While going through some old stuff Keith discovers Cordelia's diary which contains cooking with turnips. Then one page had the word 'code sorter'. Lisa realizes it's a scrambled message which turned out to be 'secret door'. Lisa pulls a rope to reveal a secret door which leads them to a dark room. Keith reads a letter from the British general for thanking Cordelia for the doughnuts. Then a box containing another secret message reveals a letter from George Washington telling Cordelia to make the doughnuts to slow the redcoats down. Lisa discovered that Cordelia made the doughnuts to distract the redcoats which shows that her ancestor was a hero. Back at the diner, Lisa offers Hector and Keith doughnuts which contains turnips.