The geeky gang will experience a fair share of relationship drama in the upcoming Valentine's Day-themed episode of "The Big Bang Theory."

Fans were finally introduced to Sheldon's (Jim Parsons) grandmother, played by guest star June Squibb, for the first time last week. However, although Sheldon was excited about spending time with his Meemaw, he was disappointed by how cold she treated his girlfriend Amy (Mayim Bialik).

Eventually, Meemaw and Amy were able to reach common ground, leaving hope for a better relationship in the future. However, in addition to shaking things up, Meemaw also dropped a huge bomb when she revealed that Sheldon has an engagement ring that he planned on giving to Amy.

Meanwhile, Raj (Kunal Nayyar) began to have second thoughts about his relationship with Emily (Laura Spencer) after meeting an intriguing woman named Claire, played by guest star Alessandra Torresani.

The synopsis for the next episode, entitled "The Valentino Submergence," reveals that each couple will experience a new challenge, while Raj will continue to grapple between exploring his chemistry with the woman he met in the bookstore and maintaining a relationship with his girlfriend. It also appears like Emily may just not be the one for Raj.

"Sheldon and Amy host a live Valentine's Day episode of Fun with Flags, Leonard and Penny grapple with getting older, Howard and Bernadette find a surprise in their hot tub and Raj is torn between Emily and the cute girl he met at the Comic Book store," it reads, according to Carter Matt.

This hints that Raj may develop more feelings for Claire since they have a lot in common.

A promo video teases that a very big "big bang secret" will also be revealed on Thursday.

Season 9, Episode 14, "The Valentino Submergence," will premiere on Thursday, Feb. 11 at 8 p.m. ET on CBS.

Watch a preview video below.

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