The Big Bang Theory Season 9 Episode 23
The Line Substitution Solution
Penny and Sheldon spend their breakfast time quizzing each other with flashcards on their respective interests.
Then Leonard asks Penny if she would pick his mother up from the airport for him.
The guys talk about an upcoming screening, but they would have to wait in lie for hours, and Sheldon already has plans with Amy.
Sheldon decides to pay Stuart to spend the day shopping with Amy in his place, so he can go to the screening.
Angry, Amy pays Stuart to go tell off Sheldon, and they begin a cycle of paying him to handle their problems.
Meanwhile, Penny struggles to get Leonard's mother to like her, and they have a girls night with Amy and Bernadette.
Beverly is able to bond with Amy and Bernadette, but she continues to ignore Penny.
Penny finally has enough and stands up for herself,and Beverly brings up the fact that she was not invited or even told about the wedding.
Sheldon gets into an argument with someone who cut the line at the screening, but they end up getting in anyway.
Penny and Beverly continue to talk, and Penny offers to have a small ceremony that everyone can be a part of.