Leonard and Penny deal with the aftermath of his Vegas confession. The marriage begins on shaky ground but the commitment is real.
Sheldon struggles with Leonard moving out eventually. The separation anxiety is real for both roommates.
The guys go on a bachelor party road trip to Mexico. The vehicle breaks down and the bonding happens in unexpected ways.
Sheldon creates a vintage vibe in the apartment to relive 2003, when life was simpler. The nostalgia trip is very on-brand.
The guys try a new sport together and the athleticism — or lack of it — creates great comedy. Sheldon discovers competition.
The gang's helium supply runs out before a crucial experiment. The scramble to find more leads to a heist-style adventure.
Sheldon discovers a vintage Leonard Nimoy documentary and it prompts deep reflection about his own life choices and relationships.
Howard sets Raj up on a date, but it's a mystery who she is. The blind date format creates suspense and comedy.
The gang spends Thanksgiving together as a platonic couples' activity. Sheldon and Amy's relationship status gets examined.
A song gets stuck in Sheldon's head and he obsessively tries to identify it. The earworm leads him to an emotional breakthrough.
Sheldon and Amy take a major step in their relationship on her birthday. The evening is planned to Sheldon's exacting standards and is genuinely moving.
Bernadette goes on a sales call and discovers she's surprisingly good at it. Raj bonds with a client in an unexpected way.
Sheldon hurts his friends' feelings and has to practice empathy. The emotional exercise doesn't come naturally but the effort counts.
Amy's grandmother Meemaw visits and she's not sure about Sheldon. Winning over the family matriarch proves to be Sheldon's biggest challenge.
Valentine's Day brings romantic pressure. Sheldon and Amy navigate gift expectations while Howard and Bernadette deal with a plumbing disaster.
Howard and Bernadette get life-changing news that shifts their priorities. The group rallies around them with support and joy.
Sheldon celebrates his birthday for the first time and the party is an exercise in controlled chaos. Amy orchestrates the milestone.
The guys file a patent and the legal process threatens their friendships. Intellectual property meets personal loyalty.
The guys build something together in the garage and the collaboration tests everyone's patience. Bernadette deals with work stress.
The gang retreats to a cabin in the mountains for relaxation. The wilderness brings out different sides of everyone.
The group watches the finale of a beloved show together and reactions are mixed. The meta-commentary on TV fandom is spot-on.
A trip to a winery creates unexpected pairings and conversations. The fermentation process mirrors the group's evolving relationships.
The gang waits in line for a movie and the queue becomes its own adventure. Patience is tested in the most nerdy way possible.
Both sets of parents converge for a wedding event, and the personality clashes are magnificent. The season ends with family chaos.