When Ron hexes the day to prove superstitions aren't real, things at the hospital start getting weird. Joyce and Matt discover an employee's secret.
Alex accidentally provokes the Emergency Department's mean girls. Ron and Serena battle over parking etiquette. Bruce has a hard time letting go of the spotlight.
Ron and Bruce butt heads over a candy bar. Alex is forced to fire an incompetent employee. Matt seeks appreciation for saving a patient's life.
When Howard dresses up as Sheldon for Halloween, Sheldon seeks retaliation at Leonard and Penny’s Halloween party; Meanwhile, Leonard is shocked that Penny doesn't remember their first kiss.
While Raj is worried that people won’t take him seriously in his own field after publishing a paper suggesting he may have discovered alien life, Penny encourages Leonard to stand up for himself when he wants to be the principal investigator on a plasma physics study.