Lisa attempts to prove everyone that she is smarter than Maggie and teaches Maggie false information. Marge, realizing this, scolds her for trying to sabotage her sister's education and that if that is how she really feels, then she should not be her sister's role model. Heartbroken, she leaves the house and hides in the Natural History Museum, where there is no chance of Homer and Marge finding her, until Chief Wiggum, Lou and Eddie find her belongings in there. The family goes into the human body exhibit, but Maggie gets distracted and accidentally presses the swallow button, swallowing Homer, Marge and Bart. Maggie presses many buttons until she finally presses the evacuate button, following a visual cue from an apologetic Lisa as to its red color.