“He's not like anybody I've ever met. He's like a riddle wrapped in an enigma wrapped in a vest. He sure is ugly, though. So why can't I stop staring at him? Oh no! I think I'm getting a crush on Nelson Muntz!”
―Lisa thinks about Nelson Muntz
"Lisa's Date with Density" is the seventh episode of Season 8.
After someone steals the Honda "H" off Superintendent Chalmers' car, Principal Skinner tries to track down the culprit. Nelson is the suspect and Lisa falls for his rebellious ways and soon develops a crush. It is now up to Lisa to change Nelson for the better. Meanwhile, Homer obtains a telemarketing machine, which drives the entire town bonkers.
At Springfield Elementary School, Superintendent Chalmers visits Principal Skinner to show off his newly purchased car – a 1979 Honda Accord – but becomes distraught when he discovers the car's hood ornament missing. Principal Skinner orders a search of everyone's lockers, lecturing the students that Superintendent Chalmers is at home crying like a girl but the lecture backfires and the student burst out laughing, and it is soon determined that Nelson is the culprit. As punishment, Nelson is forced to apologize and then help Groundskeeper Willie with chores around the school campus.
In music class, Lisa is caught looking out of the window at Nelson irritating Groundskeeper Willie, and is given detention by her music teacher Mr. Largo. In her detention, Nelson walks up to the window and comments on his surprise at her detention and once he walks away, she continues to watch Nelson, and realizes that she has developed a crush on him.
Lisa lets Nelson understand how she feels about himself after attempting to pass him a love note in class, which resulted in Nelson seriously injuring Milhouse (Nelson thought the note was from him). Lisa is resolved to reform Nelson into a model student: She changes his appearance by taking him to the Wee Monsieur (where he is dressed in a sweater and slacks) and giving him a new hairdo (Nelson states that he feels like a tool). The two later share a kiss during their date at the Springfield Observatory (this was Nelson's attempt to silence Lisa, but he chose of liking it).
However, the influence of Nelson's friends – Jimbo, Dolph and Kearney – proves to win out when they convince Nelson to throw spoiled cole slaw at Principal Skinner's house. Skinner immediately fingers the boys as suspects, and they flee. Nelson takes refuge with Lisa, proclaiming his innocence. Lisa believes him, until Nelson unwittingly lets slip the truth. Lisa realizes that Nelson is always going to be Nelson and ends their relationship, much to the relief of an overjoyed Milhouse, who had a long-lasting crush on her.
In the subplot, Chief Wiggum arrests a confidence trick scam artist for telemarketing fraud. Homer witnesses the arrest and sees the discarded autodialer in a nearby dumpster. Homer takes the autodialer to the Simpson house to use for telepanhandling.
Homer ends up annoying most of Springfield with his "Happy Dude" confidence trick scam, including Ned Flanders, who keeps answering the phone to hear the autodialer and Maude threatens to make Ned sleep outside on the lawn. This annoys Homer, and he orders them to shut up, because other people are trying to sleep. Eventually, it isn't long before Chief Wiggum catches Homer. Instead of confiscating the autodialer and taking Homer into custody, Wiggum gives him a citation and asks him to bring the autodialer with him to his court hearing. Homer does just that, and is ordered to apologize to everyone he scammed. He does so using a prerecorded message and the autodialer, and at the end of the message asks for more money.