Penny talks out her frustrations while Howard and Bernadette experience an unusual emotional breakthrough when The Big Bang Theory 9×12 airs tonight.

The Big Bang Theory returns from the holiday break tonight with “The Sales Call Sublimation,” in which the geeky gang will be grappling with some unusually weighty material.

“Penny gets more than she bargained for when Leonard agrees to meet with a psychiatrist on her behalf,” CBS says. “Also, Sheldon and Koothrappali collaborate on an astronomical discovery, and Wolowitz and Bernadette can’t believe what they are feeling after Stuart moves out.”

Specifically, the network teases that Howard and Bernadette will be experiencing “empty nest syndrome” — perhaps another step down the road toward hatching an egg of their own?

The final episode of The Big Bang Theory in 2015 was one of the series’ all-time best. Juxtaposing the monumental geek event of the release of Star Wars: The Force Awakens with Sheldon’s decision to have “coitus” with Amy, the episode saw the return of Professor Proton, took Sheldon and Amy’s relationship to a shockingly mature and tender level, and celebrated the force that is love in all its forms.

So it’s fair to say that “The Sales Call Sublimation” has a lot to live up to. But the sneak peeks from tonight’s episode indicate that it’s Leonard and Penny who will be venturing into deeper emotional territory, so hopefully the series can maintain it’s balance of humor and honesty moving forward.

Jane Kaczmarek (Malcolm in the Middle) guest-stars tonight as Leonard and Penny’s therapist. The still photos from The Big Bang Theory 9×12 feature more of Kaczmarek’s role, as well as offering a peek at Howard and Bernadette’s own emotional journey.

The Big Bang Theory 9×12, “The Sales Call Sublimation,” airs tonight at 8:00 p.m. on CBS.

What are your hypotheses for ‘The Big Bang Theory’ 9×12?