In this episode Barts class went to a desert state park. Lisa comes in contact with scorpions but learns that they calm down when around a certain flower. She takes these home for her science project. Grandfather is kicked out of the retirement home and moves in them. While Lisa spends time trying to figure out what causes the scorpions to calm down when around the flower, she extracts a liquid from the flower. When it is sprayed on the scorpions they calm down. This brings Homer an idea. He decides to use the flower liquid on Grandpa so that he will stop being so mean. It works! He realizes that when he's unhappy, nobody likes him. Lisa things that its wrong of her to do that to Grandpa because its changing the natural flow of things. When Homer is at the bar a man offers to help to figure out what it is that makes grandpa happy. After making several different concoctions they find the right now. They make it into a pill and Grandpa gets a full bottle. He is instructed to not allow anyone else to take his medicine because it hasn't been tested yet. Bart goes into the retirement home to pitch the pill even though he is not supposed to and outside there are two people doing a drug deal. It is exceptionally important to understand when and how to use drugs even if it is your own prescription. I recently lost a friend due to a bad combination of his own prescriptions. Of course nobody should be taking anyone elses prescriptions but it is also important to make sure you are taking the right dose of your own on top of making sure you have a good understanding of how one medication might react with another.