 A heatwave in Springfield leads Bart and Lisa to persuade Homer into getting a swimming pool . To avoid months of persistence , he gives in instantly . Word soon spreads that the Simpsons have a pool and every child in the town comes to use the new facility . After being dared , Bart attempts an ambitious dive into the pool from the top of his treehouse , but gets distracted by Nelson , and falls and breaks his leg . This forces him to spend the rest of the summer wearing a cast and , unable to socialize with the other children , he retreats to his bedroom . His isolation slowly makes him more and more irritable and paranoid . Lisa loans Bart her telescope to entertain him . Soon , Bart hears a woman 's scream next door , and witnesses Ned Flanders burying something in his backyard and screaming " I 'm a murderer ! " He becomes convinced that Ned has murdered his wife Maude , and vows to reveal the truth . 
