Marge comments on David and Victoria Beckham's marriage in a negative comparison with hers and Homer's, and compared the special relationship between the UK and the US to that of Mini Me and Dr. Evil in the Austin Powers films ("Helping out in all our zany schemes to take over the world"). Lisa Simpson also held a banner supporting Cornwall's secession: "UK OUT OF CORNWALL", while chanting "Rydhsys rag Kernow lemmyn" (freedom for Cornwall now).
Marge bakes a batch of delicious cookies. Bart attempts to steal them, but burns his fingers trying to pick them up. Everyone except Bart and Maggie leave the kitchen to let them cool down, and Bart takes this opportunity to swipe them, muttering to himself "Aha! The perfect crime!" Homer and Marge come back to find the tray empty. Marge suspects Maggie of eating the cookies, but as a witness she knows exactly who took them and guides them along a trail of cookies running across the floor. His family catch him lying on his back in his bedroom amidst a pile of cookie crumbs. Looking up at them with his stomach full, he groans, "There is no perfect crime." His head bangs back down on the ground and Maggie, secretively, snacks on an uneaten cookie.
Bart, Lisa and Maggie play a game of "Space Patrol" while Homer and Marge are out. Lisa plays a superhero with Maggie as her sidekick, while Bart puts a jug on his head with the pretense of it being the helmet of an alien warlord. However, his head accidentally plops into it and the jug is left stuck on his head. Lisa "frees" Bart from the jug using a croquet mallet. Lisa and Maggie then hide, allowing Bart, stumbling in a daze amongst pieces of the precious broken jug lying on the floor, to take the blame.
Marge puts Bart and Lisa in charge of babysitting Maggie. They watch TV while Maggie gets electrocuted, falls down the stairs, and falls off the roof. Maggie sticks a fork in an electrical socket thereby electocuting herself, she crawls up the stairs and falls down them in insane Slinky fashion then she climbs onto the roof in hot pursuit of a butterfly, and falls off it.
Bart and Lisa quarrel during commercial breaks over what channel they'll watch. Repeatedly Maggie comes up to the television and changes the channel. Later Homer is saying some speech about family matters then stops when the show comes back on. A piece of music from the Tracey Ullman show plays at one part or another during the short.
Good Night was the first ever Simpsons short to air on The Tracey Ullman Show. The five main family members - Homer, Marge, Bart, Lisa, and Maggie - were first introduced in this short. Homer and Marge attempt to calm their children to sleep, with the opposite results. Maggie can be heard saying "good night". She rarely talks throughout the run of the series.