Penny is forced to turn to Sheldon for help when she dislocates her shoulder in the bathtub. Meanwhile, the rest of the guys accidentally get stoned in the desert while waiting for a meteor shower.
Sheldon attempts to help Penny understand physics to impress Leonard, while Howard becomes jealous when Bernadette takes an interest in Leonard's research.
When Leonard is offered a trip to Switzerland on Valentine's Day to visit the CERN laboratory, Sheldon uses any and all means to be his guest instead of Penny.