When Sheldon "breaks up" with Amy, the guys worry when he starts replacing her with cats.

Wolowitz tries to get back together with Bernadette. Sheldon and Raj go to war at the university.

Leonard is depressed to realize all the other guys have girlfriends, while he doesn't. Amy wants to introduce Sheldon to her mother.

When Raj's sister has a one-day layover he forbids the others from hooking up with her, unaware she and Leonard already did long ago.

The rest of the gang is interviewed দ্বারা the FBI for Wolowitz's security clearance, with Sheldon accidentally letting slip some damaging information.

The guys camp out in line to see a print of Raiders of the হারিয়ে গেছে Ark with 21 extra সেকেন্ড and are outraged to see Wil Wheaton and his বন্ধু being allowed to skip the line. Penny and Bernadette invite Amy to their girls night.

When Penny's father visits, she gets Leonard to pretend to still be her boyfriend. Meanwhile, Howard, Raj, and Bernadette spend the night on an astronomy project.

Big Bang Theory tissue box!