[s7e18] The Mommy Observation -

: The gang agrees to meet for dinner in exactly 20 years. A flash-forward to Monday, March 13, 2034, reveals that only Stuart shows up for the reunion. Guest Stars Laurie Metcalf returns as Sheldon’s mother, Mary Cooper. Kevin Sussman appears as Stuart Bloom.

In the episode (Season 7, Episode 18) of The Big Bang Theory , Sheldon's surprise visit to his mother in Houston leads to a shocking discovery, while Raj hosts a murder mystery party back in Pasadena. Sheldon's "New Reality" in Houston

: After touring NASA, Sheldon and Howard drop in unannounced at Sheldon’s mother’s house. Sheldon looks through the window and catches his mother, Mary Cooper, having sex with a man named Ron. [S7E18] The Mommy Observation

: Sheldon struggles to reconcile his mother’s devout religious beliefs with her behavior, calling her a "demonic weasel" for her actions.

: Raj organizes a murder mystery dinner where Stuart unexpectedly "dies" as the first victim. : The gang agrees to meet for dinner in exactly 20 years

For more details on this episode, you can check the full recap on the Big Bang Theory Wiki or view critic reviews on Rotten Tomatoes .

: Howard helps Sheldon process the situation by sharing how he drove away his own mother's potential partners after his father left. He encourages Sheldon to support his mother's happiness instead of standing in the way. Kevin Sussman appears as Stuart Bloom

: During the game, a hypothetical scenario about the group's future leads to a discussion about where they will be in 20 years.