The Proton Resurgence
Leonard and Sheldon hire the host (Bob Newhart) of their favorite childhood TV show to perform; Bernadette and Howard run into trouble while dog-sitting for Raj's pet.

Cast
Johnny GaleckiLeonard Hofstadter
Jim ParsonsSheldon Cooper
Kaley CuocoPenny
Simon HelbergHoward Wolowitz
Kunal NayyarRajesh Koothrappali
Melissa RauchBernadette Rostenkowski
Mayim BialikAmy Farrah FowlerThe Big Bang Theory on tvt

