Boy meets his new pen friend, Gretchen and his friends get jealous when they hear 'bout it. When Boy makes cookies, they all try besides Boy, they have plans to get the cookies.
The family have been telling their deepest, darkest secrets to Cat for years. But when Cat finds one of Mouse's inventions that gives her intelligence and speech, she threatens to tell all their secrets if they don't do anything she asks.
Stevie Smith challenges Boy in the mini-golf tournament. However, as they practice, the actually become fast friends and neglect their training to hang out! When the contest arrives, it is revealed that Stevie was only pretending to be Boy's friend to keep him from practicing! But maybe Boy has a trick up his sleeve...
Mouse feeling sick of being overlooked by the family because of his small size, he builds an invention to make him grow. However, he will keep getting larger, and the bigger he gets, the more unintentionally destructive he becomes.
Boy's nose makes a weird whistling sound when he is asleep, which is no big deal unitil it is captured on video and goes viral. But is this new-found popularity a good thing?
Girl decides to write her school project about Cat, as she is so mysterious and it would be nice to know more about her. The gang decides to help her and soon, everyone is following Cat from a distance.
When Cat coughs up a magic hairball, the siblings use it to make all their decisions for them. However, when the hairball leads them to give away all their possessions, they realise it might not be so magical after all.
One day, the kids answer the door to find Wedgie, Cheese's missing piece. Wedgie is happy to have finally found her family, but she is so cute that Cheese gets jealous.
