The episode starts on an evening inside the Heelers’ house, where Bluey is playing with balloons and Chilli is blowing up the last one. Once Chilli finishes, Bluey thanks her for blowing up all the balloons. Meanwhile, Bingo runs by, giggling and wrapped in a towel, being chased by Bandit because she won’t clean her teeth after her bath. Chilli praises Bingo for having her bath, but Bandit mentions that she still needs to clean her teeth. Bingo giggles and runs off again, with Bandit chasing after her.
As they leave the living room, Chilli tells Bluey it’s time for her bath, but Bluey wants to play a game called ‘Mum School’ instead. She explains that it’s a school where you learn to be a mum, and introduces her five “children” – the balloons. Chilli is surprised and asks about another balloon that’s out of reach, which Bluey says is named Greeny and is also one of her children. Bluey uses a grabber to get Greeny down and calls him a pickle because he’s tricky to take care of. Chilli offers to run the bath, but Bluey says it’s not time yet. Bluey tells Chilli that she’s the lady who gives her a score for being a good mum, but then lets go of Greeny, saying “Not again!” as she tries to get him down with a cushion.
The scene cuts to Bluey pushing the sofa closer to the TV, where the “children” are going to watch a movie. Bluey tells them to sit up straight and not sit on top of each other, and moves Lightning Bolt off Winddust, which causes Greeny to float up. Bluey grabs Greeny and tells him to hold her hand, earning her two points from Chilli for good mothering. As Bluey tries to turn on the TV, Greeny keeps bumping against her, and she tells him to hop over to the couch. However, Greeny “pushes” Winddust, and Bluey puts a cushion on top of him to keep him from floating away. Chilli praises Bluey for good mothering when she scolds Winddust for calling Greeny a ‘cushion head’.
The “children” eventually fall off the couch, and Chilli suggests they go to the ‘indoor pool’ for exercise. Bluey agrees and tries to lead them there, but gets frustrated when they don’t walk in a straight line. She grabs a wrapping paper roll, called “Bunty”, to try and keep them in line, but Chilli tells her that’s not a good idea. The scene cuts to the bathroom, where all the “children” are in the tub except Greeny, who is under a basket. Bluey talks to Greeny and asks if he’ll behave himself if she lets him out, but Chilli says she knows the answer. Bluey is confused about what to do, but then watches as Bandit tries to get Bingo to clean her teeth in the shower.
Bandit eventually succeeds in getting Bingo to clean her teeth, and Chilli gives him two points for making it fun. Bluey thinks about what to do with Greeny and decides to give him another try. She realizes that Greeny might like exploring, and gives him a special gift – a magnet shaped like the letter “G” – to help him stay down with his family. Bluey tells Greeny that one day he’ll be able to explore far and high, and hugs him. The “children” all get in the “pool”, and Chilli praises Bluey for her good mothering.
After their swim, Bluey and her “children” get dried, and Chilli tells Bluey that she’s almost passed Mum School. Bluey gets excited and wants to use the hair dryer, but ends up blowing her “children” away and apologizing. She sees Greeny floating out of the bedroom and outside, and tries to save him with Chilli’s help. However, they can’t reach him, and Chilli tells Bluey that Greeny will be okay because he’s got a good mum. Bluey asks if she failed Mum School, and Chilli says she did, but she can try again tomorrow. Bluey thanks Chilli and the episode ends.
