Morticia reveals she’s pregnant to her family. At the hospital, she’s giving birth. Wednesday and Pugsley argue over his gender, with Wednesday thinking he's a girl and Pugsley thinking he's a boy. Gomez then enters the room and proclaims he is an Addams.
Later on, Morticia puts him in his crib. Wednesday and Pugsley start worrying about the tradition that when a baby comes, one of the older children must die. Wednesday then says they need only one boy, much to Pugsley's dismay. They then watch the family crowd around Pubert and watch as he shoots a flaming arrow. Wednesaday then twists the head off a doll, foreshadowing their upcoming sibling rivalry.
Wednesday and Pugsley kidnap Pubert and stand on top of the building. Wednesday decides to play a game and has Pugsley hold a cannonball while she holds Pubert. She wants to see which will hit the ground first: Pubert or the cannonball. She drops Pubert while Pugsley drops the cannonball. However, Gomez had openned the door at the same time and caught him while the cannonball hit Lurch on the head.
The parents question the children as to why they hate the baby so much, but they say they only want to play. The parents correctly assume they think they love the baby more than them and thinks one child must die when the baby is born. As it turns out, it used to be true but isn't anymore. However, the kids kidnap Pubert again. This time, they try to decapitate him with a guillotine, but he grabs the blade.
The family employs several nannies, but the kids scare them away, until they employ Debbie Jellinsky. The children trick Pubert into crawling under an anvil, and drop it, but Debbie picks him up and walks away before it can crush him. Later on, Wednesday spies on Debbie and Pubert. Oddly enough, shortly after, she seems to take offense to Debbie calling Pubert a brat.
After Fester Addams leaves the family for Debbie, he becomes sick and turns normal, with fair skin and blonde hair. However, when Fester returns, finding out Debbie is a serial killer who plans to kill him and steal his fortune, Pubert returns to normal. The family is captured by Debbie, and Pubert uses a knife to cut out of his crib and ends up soaring through the air and into the house Debbie and the Addamses are in. As Debbie pulls a lever to electricute the family, Pubert connects the wires, sending the electricity to Debbie, killing her. He then laughs as he sees the ashes that were once Debbie.