Big Bang Theory
Howard (Simon Helberg, left) and Raj (Kunal Nayyar) start a band in episode 4 of "The Big Bang Theory" Season 9. CBS

Sheldon (Jim Parsons) has not been coping with his breakup from Amy (Mayim Bialik) too well in "The Big Bang Theory" Season 9. In episode 2 he ended up insulting her by taping a vengeful episode of "Fun with Flags," and then in episode 3 he had to be tied up and blindfolded to go on Leonard's (Johnny Galecki) bachelor party. However, episode 4, "the 2003 Approximation," might be the one where Sheldon finally cracks.

According to the synopsis for the Season 9 installment, Sheldon will snap when Leonard reveals that he is moving in with Penny (Kaley Cuoco), now that the longtime couple are actually married. Sheldon has had a rough time as it is with his breakup and the prospect of living alone will be just a bit too much for him to take. In his panic, Sheldon will revert back to his more neurotic 2003 self, leading to a lot of drama and headaches.

There may be another reason for the headaches as well -- Howard (Simon Helberg) and Raj (Kunal Nayyar) are starting a band! The pair are putting together a little music ensemble to play in the comic book store and things are going to get interesting. The promo for the episode reveals that the duo's songwriting muses will be Thor and Indiana Jones, resulting in the world's nerdiest rock opera.

"Remember the Ark of the Covenant," says Raj, alluding to the "Indiana Jones" movies. "That's how much we are going to melt people's faces with this band."

That may be setting the bar a little high.

Watch the promo for episode 4 below:

What will happen when Sheldon reverts back to his 2003 self? And how will Howard and Raj's band turn out? Fans will have to wait to find out. "The Big Bang Theory" airs Mondays at 8 p.m. EDT on CBS.