The Big Bang Theory

• S12 E25 - Episode 25

• S12 E24 - Unraveling the Mystery: A Big Bang Farewell

• S12 E23 - The Change Constant / The Stockholm Syndrome

The sitcom is centered on five characters living in Pasadena, California: roommates Leonard Hofstadter and Sheldon Cooper; Penny, a waitress and aspiring actress who lives across the hall; and Leonard and Sheldon's equally geeky and socially awkward friends and co-workers, mechanical engineer Howard Wolowitz and astrophysicist Raj Koothrappali. The geekiness and intellect of the four guys is contrasted for comic effect with Penny's social skills and common sense.