In this week’s Big Bang Theory, “The Cooper Extraction,” Amy and Penny are playing an interactive video game while Leonard sits out icing his foot with a “video game injury.” Sheldon informs the group that he has to leave to go to Texas since his sister is having a baby.
When Sheldon leaves, the gang decorates for Christmas without Sheldon’s strict rules, such as using an ornament spacing template. Stewart comes in and joins the group. Sheldon calls and sees that everyone is over at what looks to be a Christmas party. He thanks them for being so thoughtful for now making him have to be a part of it. Sheldon’s call gets cut short when he is informed that his sister is about to give birth.
Bernadette suggests that they all should watch It’s A Wonderful Life. They start to think about what life would be like without Sheldon. Amy points out that if it wasn’t for him, they may not all know each other and be sitting there together. Leonard says that he always went to the Cheesecake Factory, so he still could have ended up dating Penny. Penny disagrees and she explains what would have happened, which includes him getting too scared to ask her out and peeing his pants.
Amy says that Leonard living with Sheldon is the reason he met Penny and that Penny was the one that set up Howard and Bernadette. The gang then plays out a few more scenarios.
Sheldon calls back being disturbed about the things he has seen. Amy assures him that lady parts don’t normally look like that. He later sends them a picture of his sister giving birth which they are all disgusted by.
Bernadette realizes that even if Leonard didn’t move in with Sheldon, Penny would still live across from him. Amy imagines that Penny would hit on Sheldon with Leonard being out of the picture. She says Penny would come on to him in the laundry room by taking her shirt off, but he would decline saying he is saving himself for a smart neuroscientist.
The gang results to making a chart to figure out the relationships with and without Sheldon in the picture. They start to speak about Howard and him living with his mom. Bernadette says that if it weren’t for her, he would still be living with his mom. Howard explains that it would be different because his mom would be dead, not revealing if he would be the one to kill her or not.
Raj imagines a Leonard being fat if they ended up living together since he would have no girl friend so he would eat from depression. Leonard points out that Raj would be fat, too. Stewart them interrupts saying that he would show up, also fat. He says that he wants to be in someone’s story.
Penny asks Amy what she would be doing without Sheldon. She imagines being alone singing happy birthday to herself with a cupcake. She turns to her side and looks at Stewart sitting next to her with a party blower.
Sheldon calls again and tells the group that his sister had a boy. He says that the baby is so irritating as it has been crying it’s entire life. Amy suggests that he should go spend time with the baby so he can be a role model to him, just like he had always wanted a role model. Sheldon agrees.
The gang tells Amy that she has also had an impact of Sheldon, but she doesn’t seem to see it. Leonard decides to show her that she is Sheldon’s screensaver. She notices that the picture changes to different people he likes such as Swamp Thing, but Amy is happy that she is in the mix.
Sheldon gets back from Texas and walks up to the apartment with Amy. Amy tells her that she missed him and when she asks him if he missed her, he says that it would have been preferable if she was there with him.
At the end, Stewart imagines that he is Penny’s boyfriend and the other guys are fat and eating at the Cheesecake Factory.