In tonight’s Big Bang Theory, Kripke brings Amy a bottle of wine to thank her for helping him with his research. Sheldon gets jealous because she helped him make an advancement in string theory, his former area of study. Amy points out that she tried to help him when he hit a dead end, but Sheldon made fun of the math skills of biologists.
Sheldon explains his frustration to Penny, upset that she helped his rival. Penny suggests that he lets it go or talk to her more about it. He doesn’t like either suggestion. Penny continues to try to teach him let the situation go, but he isn’t budging. Sheldon tells Penny that maybe he can learn by her example. He reveals that Amy has secretly been giving her little puzzles so she can test her intelligence against the chimpanzees in her lab. Penny thinks about it and realizes that she has been being presented with these puzzles. This makes her angry, but Sheldon tells her to let it go, just like she has been telling him.
Sheldon explains that he thought some of the puzzles she was giving the chimps would be too hard for some humans to solve. That is when they decided to make it interesting by getting Penny involved. Penny gets mad at Sheldon, and he doesn’t understand why. He thinks that she should be taking her frustrations out on Amy. She kicks him out of her apartment.
When Amy goes to see Sheldon, Penny hears her in the hallway so she comes out and confronts her. Sheldon hides in the apartment and Amy tries to defend herself.
Penny later tells Leonard about the puzzles. Leonard remembers that Sheldon gave him one of the same puzzles, which was getting a banana out of a puzzle box. He realizes he was being tested as well. To Penny’s surprise, he mentions that he was unable to solve that puzzle meanwhile she succeeded.
The two of them go to confront both Amy and Sheldon at the comic book store, but it just results in more bickering.
In tonight’s subplot, Howard is still jealous that Stuart is staying with his mom, but he hopes things will get back to normal because the comic book store is reopening.
The new comic book store is all set up. When they go to look at the new store, Howard notices some of his mom’s furniture is a part of his new seating area. This upsets Howard and they get into an argument because he thinks Stuart is mooching off of his mom.
Howard feels like the furniture that he grew up with should be in the home he grew up in. Bernadette points out that if the store succeeds then Stuart will have a source of income that will allow him to move out of his mom’s house. Howard reluctantly agrees that she has a good point.
With the gang all at the store, Howard gets a devastating call that his mom passed away while vacationing in Florida. Sheldon, instead of saying something inappropriate, tells Howard that unlike when his dad died, he will have friends to help him through it.
While Bernadette and Howard are at the airport to head to Florida, the gang reminisces about their memories of Mrs. Wolowitz and toast to her.
Tonight’s episode was a tribute to Carol Ann Susi who portrayed Mrs. Wolowitz. She lost her battle with cancer this past November.