Billy wanted Mandy and Grim to be positive, but she keeps telling him that he cannot force changes in other people. I have to agree with Mandy, because some people are fine the way they are. When Billy met Mary Frances, he's been trying to get her to be nice. But instead, she'd rather be a jerk like the rest of the other unicorns. Even though Mandy hates unicorns, she actually likes hanging out with Mary Frances because of her negative attitude. So Grim and Mandy replaces Mary Frances with Billy.
While Billy, Mandy, Grim, and Irwin are trapped in a well with a sea serpent, Billy told the story of how he and Mandy first met Grim. It was based on one of the "Indiana Jones" movies. One part where Billy makes Mandy look like a nice person, Mandy gets ticked off, and changed him mind about her. Grim explained how he first met those two kids. His side of the story was based on "Star Wars" and the capture was like in the "Ghostbusters" series. Mandy told the real origin that took place since this series began. It was from the first episode made by Maxwell Atoms. In the end, the gang gets devoured by the sea serpent.
So many episodes of Billy and Mandy, yet they can be quite interesting at some time. Irwin now knows how Billy and Mandy first met Grim. Sadly, Irwin made his first appearance from "Get Out of My Head".