Name: The Line Substitution Solution
Genre: Comedy
Duration: 25 min

ALLTV

Leonard's recently divorced parents and Sheldon's devoutly religious mother visit; when they are contacted about their guidance system, Wolowitz and Koothrappali think the government is after them.

The Big Bang Theory

The Convergence Convergence

Sheldon wants to go to a movie screening, so he pays Stuart to spend the day with Amy; Penny has a difficult time connecting with Leonard's visiting mother.

The Line Substitution Solution

The gang runs into Penny's old boyfriend while out at a wine bar; Bernadette spends an evening with Sheldon; Koothrappali's introduction of his new girlfriend doesn't go as planned.

The Fermentation Bifurcation

During a group get-together, a minor argument between Sheldon and Leonard turns into a heated debate, leaving the rest of the gang to choose sides.

The Viewing Party Combustion

Sheldon shares a secret about Leonard when the two go on a weekend trip with Penny and Amy; Koothrappali goes all out with pregnancy gifts.

The Big Bear Precipitation

Sheldon makes a surprise revelation when Amy buys him a new laptop; Leonard and Wolowitz get sold out by Koothrappali after lying to their wives to attend a movie screening.

The Solder Excursion Diversion

Leonard, Sheldon and Wolowitz file for a patent on their new invention; Penny, Amy and Bernadette give dating advice to Koothrappali after his breakup with Emily.

The Application Deterioration

For the first time in nine years, the gang celebrates Sheldon's birthday -- surprising him with a special guest.

The Celebration Experimentation

The gang celebrates news of Bernadette's pregnancy by singing karaoke; Wolowitz's reaction to the pregnancy announcement worries Bernadette; Wolowitz believes he needs to make more money to support his growing family.

The Positive Negative Reaction

Amy and Sheldon host a Valentine's Day edition of Fun With Flags; Penny and Leonard wrestle with getting older; Howard and Bernadette make a discovery in their hot tub; Raj is torn between Emily and another woman.

The Valentino Submergence

Sheldon's excitement about his Meemaw's visit fades when she butts heads with Amy; Raj questions his relationship with Emily after meeting someone new.

The Meemaw Materialization

After dealing with Sheldon while he was sick, Leonard, Penny and the gang attempt to treat themselves to a Sheldon-free weekend.

The Empathy Optimization

Watch TV Networks, Shows and Movies | DIRECTV

The latest movies and must watch shows!

Watch The Pitt exclusively on the HBO Max app, included with an HBO Max subscription.

Data/messaging rates may apply for app download/usage. HBO Max subscription required.

Welcome to your ultimate entertainment destination. Watch new episodes of School Spirits and more all in one network.

Watch exclusive originals like heartfelt comedy American Classic, Hollywood hit movies & more.

MGM+ is a trademark of Metro-Goldwyn-Mayer Lion Corp. All copyrights, trademarks, and other intellectual property or proprietary rights are the property of their respective owners.

Watch visionary original series like Outlander, Outlander: Blood of My Blood, Spartacus: House of Ashur, Power Book, BMF and much more.

Physicists and best friends Leonard and Sheldon learn about the social aspects of life through their relationships with the free-spirited beauty who moves in next door.

S9 E23 | The Line Substitution Solution