While hanging out in her room, Luna is chatting with her poster of Mick Swagger, asking how she can get $50 for a VIP pass to his upcoming concert. Suddenly, Luna hears a knock at the door and answers it, where it's revealed to be Clyde, Howard and Harold. Clyde explains to Luna that he and his dads are heading to a McBride family reunion and need somebody to babysit their cats Cleopawtra and Nepurrtiti since their usual pet-sitter cancelled at the last minute. When Luna realizes that she could get paid this way (and because Sam has her VIP pass), Luna promptly asks if she can babysit, and the McBrides agree on the condition that she doesn't bring anyone else with her, since the cats get anxious when there's more than one person.
At the McBride house, Luna discovers, to her shocking surprise, the manual on how to take care of the cats, which is revealed to be massive. She first reads that the cats need to be fed by 10:00 or they'll be cranky. However, it's 10:02, and the cats promptly attack Luna after she grabs the food. Next, Luna tries to walk the cats, but they go faster than Luna can handle. Afterwards, Luna tries to give them a bath because of all the food stuck to them, but when cats hear Luna utter the word "bath", the cats run off, prompting Luna to chase after them, ending it with her falling in the bathtub. When Luna bemoans to Mick on how little progress she's making, she suddenly gets the idea to call Sam, since she's an animal expert, much to Mick's disapproval, since she can't have anyone else with her.
Sometime later, Sam arrives and reveals she brought along her younger brother, Simon. Despite some hesitance, Luna lets Simon in and convinces him to play with Clyde's VR headset. Throughout the night, Luna and Sam manage to take care of the cats with ease. After Luna and Sam get the cats to sleep by singing a lullaby, Sam leaves, but to her horror, Simon is still in the house and Luna unknowingly locks her out. Sam tries to enter through the front door, but the McBrides arrive back at that moment, forcing her to hide in a bush. Luna opens the door and lets the McBrides in, but upon seeing Simon still in the house, Luna attempts to prevent them from seeing him. After a few mishaps and close calls, Luna attempts to shove Simon out the window, but is caught by the McBrides.
Later, as Luna confesses that she brought someone over to help, she decides to give the money back to Howard and Harold. However, when Howard and Harold state that they appreciate her honesty, they're also impressed at how well they took care of the cats, so they decide to split the money evenly between them, and Sam immediately gives her half to Luna so she can buy her VIP pass. At that moment, the cats enter the room, having been woken up by Luna cheering. Luna and Sam quickly put the two cats back to sleep with their lullaby that even the McBrides, Simon and Mick (in Luna's thoughts) fall asleep to as well.