Lisa invents a family history including a fake Native American tribe to impress everyone for the diversity project at school. As she gains more notoriety for her incredibly detailed story, Lisa feels more and more guilty yet keeps the farce alive hoping it will all blow over. When she finally admits to the fabrication, she must endure sensitivity training. Meanwhile, Bart discovers a nearby town and meets a girl who he thinks got pregnant from kissing him - his first kiss. They decide to run away and get married to start a new life together because the girl is afraid of telling her parents about her situation.