In last night’s Big Bang Theory “The Itchy Brain Simulation,” Leonard finds a movie rental that he was supposed to return seven years ago. The rental is on Sheldon’s card and although Sheldon does not make a big deal of it, he says that unresolved issues make his brain itch. Sheldon proposes that Leonard should wear an old itchy wool sweater so he can understand how he feels. This becomes a much more difficult task when Leonard finds out that the DVD rental store closed down. Leonard refuses to take off the sweater. He plans to wear it until the issue is resolved in order to prove a point.

Leonard tries to track down the owner of the closed store, but finds that he had passed away. Howard mentions that it can be returned to the next of kin, so Leonard keeps the sweater on. By this point, the sweater has burned Leonard’s skin and has given him a rash.

Leonard shows Penny his bad rash and she asks him why he doesn't just take it off. Leonard explains that if he does, Sheldon wins. Penny then points out to him that everytime he doesn't kill Sheldon in his sleep, Sheldon wins.

Meanwhile, Penny confronts Raj’s ex-girlfriend Lucy who she sees eating at the Cheesecake Factory. She tells her that she is a bad person for breaking up with Raj in an e-mail. When Penny tells Raj, he gets upset at her. That is, until he receives a text from Lucy asking to meet. The meeting however doesn’t turn out well. Lucy apologizes for the way she ended things, but then she reveals that she is dating somebody else. This makes Raj made at Penny again, but he forgives her when she tells him she will set him up with someone from the Cheesecake Factory.

Leonard still on his mission to find someone to return the DVD to finds that there is no next of kin. Defeated with itchy red skin, Sheldon decides to reveal his diabolical plan, as Amy calls it. Sheldon informs Leonard that he has paid for the DVD seven years ago when he found out it was late. He decided not to tell Leonard because he thought that one day it would be a “teachable moment.” Leonard, who is upset, takes off the sweater and runs over the fridge to get frozen vegetables to put on his chest.

At the end of the episode, Raj meets a woman from the Cheesecake Factory like Penny promised. He, of course, makes inappropriate comments and things don’t end well. The woman ends up yelling "what's wrong with you!" at Penny for setting them up, followed by Penny yelling at Raj, asking what is wrong with him.