When Sheldon calculates the technology to download his consciousness into a robot won't be invented soon enough, he desperately tries to find a way to increase his lifespan.
Following his 'breakup' with Amy, the gang become concerned with Sheldon's obsessive search for non-human companionship and call his mother to intervene.
Howard tries to get Penny's help in winning back Bernadette, but first has to confess the embarrassing reason why they broke up in the first place. Raj and Sheldon clash over a desk.
Sheldon is scared that he is in a relationship when Amy asks him to meet her mother, and Leonard asks Howard and Bernadette to set him up because he is the only person in the group without a girlfriend.
Leonard tries to keep everyone from finding out that he spent the night with Raj's sister, but Sheldon finds out and concocts an elaborate story to help him keep the secret from Raj.
Penny asks Leonard to pose as her boyfriend when her father visits. Howard, Raj and Bernadette have an awkward encounter when they spend the evening together.
Amy discovers some unusual feelings and urges when she meets Penny's ex-boyfriend, Zack. Meanwhile, Howard and Raj argue over who would be a superhero and who would be their sidekick.
Bernadette makes Howard choose between herself and his mother, while Penny and Raj become upset when Priya returns to town and resumes her relationship with Leonard.
Sheldon invents a three-player chess game, Penny and Amy use Bernadette to spy on Leonard and Priya, and Raj tries a new drug to treat his social anxiety.
Howard believes that his mom suffered a heart attack because he told her that he's marrying Bernadette, Sheldon freaks out over germs, and Penny and Priya compare notes on Leonard.