A British filmmaker comes to Bart's class to make a documentary on the typical American school, and Bart's celebrity status is plunged into jeopardy when Nelson receives attention from the filmmaker for stealing hood ornaments.
Moreover, the filmmaker leaves Lisa with feelings of inadequacy, causing her to run out and choose a career in astronomy. Bart begins searching for unique hood ornaments while Lisa, unable to find a dark spot to stargaze, climbs Mt. Springfield. She encounters Professor Frink at the summit, and he teaches her about the problem of light pollution. Lisa starts a campaign to reduce the amount of light usage in Springfield, but when Chief Wiggum encourages Springfield to double its light usage to fight crime, night becomes day and the town goes "mondo bizarro," unable to sleep with the constant light.
Lisa finally decides that enough is enough and breaks into the power plant with Bart, overloads the system and plunges the town into total darkness, returning Springfield to normal.