When competitors Pemberton and Campbell charm America on a publicity tour, Sheldon and Amy try to win over Nobel laureates Kip Thorne, George Smoot and Frances Arnold; Halley's fear of the dark leads to opportunity and conflict.

Cast: Johnny Galecki, Jim Parsons, Kaley Cuoco, Simon Helberg, Kunal Nayyar, Mayim Bialik, Melissa Rauch, Kevin Sussman, Frances H. Arnold, Sean Astin, Joshua Malina, Kal Penn, George Smoot, Kip Thorne