'Big Bang Theory' Season 9 Spoilers: Episode 15 Synopsis Released; What Will Happen In 'The Valentino Submergence'?

With every main character on CBS’ “The Big Bang Theory” involved in a serious relationship in Season 9, the celebration of Valentine's Day has never had higher stakes than it does now. In “The Valentino Submergence,” every character pairing will be put to the test as the gang tries desperately to get through the holiday with no lasting damage.

According to the episode 15 plot synopsis, Sheldon (Jim Parsons), Amy (Mayim Bialik), Leonard (Johnny Galecki), Penny (Kaley Cuoco), Howard (Simon Helberg), Bernadette (Melissa Rauch), Raj (Kunal Nayyar) and Emily (Laura Spencer) will each struggle to make Feb. 14 the most romantic day ever. Sadly, that turns out not to be an easy task.

“Sheldon and Amy celebrate Valentine’s Day with an episode of ‘Fun With Flags’; Leonard and Penny feel the pangs of aging; Howard and Bernadette are surprised by what they find in their hot tub; and Raj can’t decide between Emily and the comely woman he met at the Comic Bookstore,” the synopsis reads.

It’s unclear exactly who is having the toughest time in the upcoming episode, but the synopsis seems to build off a difficult conundrum for Raj that started in last week’s episode. After meeting a very attractive and fun writer, the character finds himself questioning if he’s really supposed to be with his current girlfriend, Emily. The couple hasn’t had as much of a romantic back story as their friends, and it seems their feelings for each other and their future together will have to finally be addressed now that the holiday of love is upon them.

While Raj certainly has a lot of heavy emotional problems to deal with, Sheldon and Amy may be in bit of extra trouble this Valentine’s Day as well. A TV spot for the upcoming episode (below) teases a big secret that will shake the very fabric of their relationship, more than Sheldon’s Meemaw did during last week’s episode, apparently.

“The Big Bang Theory” Season 9, episode 15 airs Thursday, Feb. 11, at 8 p.m. EST on CBS.