The Big Bang Theory season 7, episode 18 airs tonight on CBS! Here’s the preview and everything you need to know about “The Mommy Observation.”

Sheldon will see an upsetting side of his mom tonight when The Big Bang Theory season 7, episode 18 airs on CBS. The episode, tellingly titled “The Mommy Observation,” sees Sheldon deal with the consequences of catching his mother in a compromising position with the new man in her life. Back in Pasadena, Raj will entertain the gang with a Murder Mystery party that doesn’t go quite as planned.

The official synopsis for “The Mommy Observation” gives an overview of the unexpected events.

When Sheldon visits his Mom in Houston, he is forced to confront a new reality. Meanwhile, Raj’s ‘Murder Mystery’ party starts some fights within the gang.

On last week’s episode of The Big Bang Theory, Sheldon and Howard were forced to confront how much they meant to each other during a turbulent flight down to Houston. Meanwhile, Leonard proved why he is a ridiculously good boyfriend, and Raj left absolutely no doubt in anyone’s mind as to why he is still single – at Amy’s expense.

The preview for The Big Bang Theory season 7, episode 18 focuses on the mystery in Pasadena, as well as Sheldon’s relationship with his mother.

A new sneak peek from “The Mommy Observation” sets the scene for and then features said observation. Much to Sheldon’s horror and Howard’s bewilderment, Mrs. Cooper is left with few mysteries to hold back from her neurotic son.

Still photos from The Big Bang Theory season 7, episode 18 offer a few more hints as to what will go down in tonight’s episode. If nothing else, we know that poor Stuart is an in-game goner.

The Big Bang Theory season 7, episode 18, “The Mommy Observation,” airs tonight at 8:00 p.m. on CBS.

How do you think Sheldon will respond to his mommy observation?