The Simpsons has a lot of inconsistencies and plot holes that fans have been trying to solve, among those when Lisa bought Bart’s soul and how she knew where to find it. Over the years, The Simpsons has touched on various topics, the most common ones being politics and religion, and it has sometimes delved into more philosophical realms, like that one time it dealt with Bart’s soul.
In over 30 seasons, The Simpsons has dealt with the various personal and social issues of each member of the title family, and in season 7’s episode “Bart Sells His Soul”, Bart decided that he didn’t believe in “souls”, and without even thinking it twice he sold his to Milhouse in the form of a piece of paper for $5. To Bart’s surprise, it turned out that he did have a soul, which allowed him to do many things – from laughing at his favorite TV show, to automatic doors opening for him. Though Milhouse did believe in souls, he didn’t really take Bart’s seriously, and played with the piece of paper, asked for a big amount of money in return just to mess with him, and ended up trading it to Comic Book Guy for Alf pogs.
The big surprise of the episode is that, after learning that Comic Book Guy sold his soul to an undisclosed costumer, Bart goes back home and prays to God for his soul, with Lisa arriving with it. As it turns out, Lisa bought it from Comic Book Guy, and while she tried to explain the philosopher’s opinions on the human soul, Bart ate the paper and proceeded to have a dream where he and his soul made Martin and his soul drown. Although Lisa buying Bart’s soul is a nice moment between the siblings, it represents a minor plot hole that some fans have tried their best to solve: when did Lisa buy Bart’s soul, and how did she know Comic Book Guy had it?
Some fans believe that by the time the Simpsons were having dinner at Uncle Moe’s Family Feedbag, Lisa was already in possession of Bart’s soul, which is why she taunted Bart with a prayer even though she had been on his side the whole time. However, this represents a timeline problem, as Comic Book Guy told Bart he sold his soul the previous night, so she should have bought it after dinner – unless Comic Book Guy has a different concept of “night”. As for how Lisa knew where to find Bart’s soul, the safest bet is that she got to talk to Milhouse before his family went to his grandmother’s house, and told her that he traded them for the pogs.
Another detail that has bothered some fans is Lisa’s attitude at dinner, which has been interpreted in different ways. While some see it as one Lisa’s self-righteous moments, others believe it was a way to buy some time so she could purchase the soul without Bart knowing, with some believing that she already had the soul and was simply messing with him so she could surprise him once she was finished, but he ran away. The easiest way to solve the plot hole would be with Lisa talking to Milhouse earlier that day, then buying the soul after dinner, and the prayer being one of her ways of teaching her brother a lesson, even if it turned out to be mean. Compared to other plot holes in The Simpsons, this isn’t one that ruins the story or even one that’s evident to all viewers, but it can be fun to explore.