Bart finds new respect for the law and Lisa hangs out with the wrong crowd after they both take career aptitude tests.
Bart and Lisa take a career aptitude normalizing test at school to determine what jobs suit them best. Lisa is heartbroken when her test shows her ideal career is a housewife. To Bart’s surprise, his test shows he should be a police officer. Having hoped to be a blues saxophone player, Lisa is determined to prove the test wrong. She goes to an acclaimed music teacher to get his opinion on her musical prowess. Lisa is informed, that due to a hereditary problem from Homer’s side of the family, she has stumpy fingers and can never be any good on the saxophone. Bart gets a ride-along with Eddie and Lou to see what it’s like being a cop. During the ride, they are involved in a high speed pursuit and Bart is nearly run down by a robber. Bart decides being a cop is cool.
Learning that she will never be any good on the sax, Lisa loses interest in being a good student and falls in with the wrong crowd. Practicing to be a cop, Bart turns Grounds Keeper Willie in for burning leaves. Impressed with Bart’s new-found respect for the law, Principal Skinner asks Bart to be the school’s official hall monitor. Finding out he will get to wear the official “Hall Monitor” sash, he jumps at the opportunity. Soon Bart has cleaned up the school of undesirables.
As Bart’s grades show slight improvement, Lisa’s fall by the wayside. To prove her loyalty to her new trouble-maker friends, Lisa steals all the teacher’s editions of the school books. Without their books, that have all the answers in the back, the teacher’s are left helpless. Skinner enlists Bart’s help to track the thief down. Bart discovers the books in Lisa’s locker. Realizing Lisa will be expelled and will not be able to lend him money, Bart decides to take the rap for her. He is stripped of his sash and given 600 days of detention. Thankful for his chivalry, Lisa plays her saxophone beneath Bart’s classroom window while he serves out his sentence.
Source: 20th Century Fox