The Big Bang Theory season 9
Penny and Beverly in The Big Bang Theory season 9 episode 23 pictures CBS

The Big Bang Theory season 9 returns with a new episode this Thursday, where Penny will struggle to strike a chord with her mother-in-law Beverly Hofstadter. Episode 23 is titled, The Line Substitution Solution, which will air on 5 May at 8pm EST on CBS Network.

The official synopsis reads as follows:

Click here to watch the episode via live stream online on CBS All Access. You can also click here to watch it online (only in the US).

A promo for the episode shows Beverly telling Amy and Bernadette that she wants to interview both of them, including Sheldon and Howard as she is planning to write a book on high-achieving couples.

Penny is clearly annoyed by this discussion, and says to her mother-in-law, "This is ridiculous. I have been trying to make a connection with you all day and clearly I am getting no-where."

Beverly replies, "Are you seeking a connection or just some form of validation." A mad Penny replies, "What I was seeking is some sort of friendship. At this point I will take you not insulting me to my face."

"My intention was never to insult you," says Leonard's mother, but Penny points out that she has insulted her all day and asks, "Do you not know what an insult is?"

A calm Beverly points out the reason she is not happy with her. She says, "It's not a clinical term, but one example would be your marrying my son, and not inviting me, or even telling me that the wedding was taking place."

Penny takes a few moments and ends the whole debate saying, "Okay! Good example."