As a joke, Sheldon and Penny try an experiment designed to make participants fall in love. Also, Leonard, Amy, Raj and Emily spend the evening trying to escape a room with a “zombie.” And, after returning from Mrs. Wolowitz’ funeral, Bernadette and Howard run into trouble at the airport.
Elenco: Jim Parsons , Johnny Galecki , Kaley Cuoco , Simon Helberg , Kunal Nayyar , Mayim Bialik , Melissa Rauch , Kevin Sussman , Aarti Mann , Kevin Sussman , Sara Gilbert .