Penny and Leonard organize a paintball game, which results in mayhem when Sheldon becomes jealous of Amy. Raj catches Anu with her ex-boyfriend. Stuart doesn't want to move in with Denise.
Sheldon and Amy are thrilled when their super asymmetry theory is proven by two physicists, until they try to kick Amy off the Nobel nomination. Bernadette gets one of her drugs approved and wants a reluctant Penny to head the sales team.
Sheldon is thrilled to help Bernadette and Howard navigate bureaucracy concerning a neighbor's non-compliant balcony until he learns they too have ignored codes. Leonard is disappointed when his friends are uninterested in his new laser.
Penny tries to throw a wrench into Leonard's plan to be a sperm donor for her ex-boyfriend; Wolowitz, Bernadette, Anu and Koothrappali turn Koothrappali's canceled bachelor party into a couple's trip aboard the "vomit comet."
The gang finds out Wil Wheaton hosts a celebrity Dungeons and Dragons game involving William Shatner, Joe Manganiello, Kareem Abdul-Jabbar and Kevin Smith. Deception and betrayal are the path to make it to the one open seat.
Bernadette and Penny travel to San Diego for a pharmaceutical sales convention. Back home, Amy and the guys experiment on the Wolowitz children when Sheldon finds a book on it.
Rivals Pemberton and Campbell charm America on a publicity tour so Sheldon and Amy try to win over Nobel laureates Kip Thorne, George Smoot and Frances Arnold. Halley's fear of the dark causes opportunity and conflict at the Wolowitz home.
Contemplating what it would mean to all women if she were to win a Nobel Prize causes Amy to have a meltdown. Koothrappali and Wolowitz try to relive the good old days after Wolowitz buys a scooter that looks like the one he had years ago.
Koothrappali is worried people won't take him seriously in his own field after publishing a paper that suggests he may have discovered alien life. Leonard wants to be the principal investigator on a plasma physics study.
Kripke has proof that Dr. Pemberton plagiarized his thesis in college, and Sheldon and Amy aren't sure if they should turn him in. Wolowitz learns that Bernadette wasn't the only waitress at the Cheesecake Factory who had a crush on him.
Leonard is pleasantly surprised when Beverly comes to visit and she's genuinely kind to him, until he finds out the real reason she's there. Also, Denise and Stuart overstay their welcome at the Wolowitz house.
Bernadette and Wolowitz leave their kids for the first time; Penny and Leonard try to keep a secret; Sheldon and Amy stick together; and Koothrappali makes a new friend, as the gang travels together into an uncharted future.