CHIN's

Hayley's plan for a fun-filled girl's day with Rainer Shine's teen daughter may be a little more angst-filled than expected. Meanwhile, Luke finds himself in a compromising position with a widow at the club and unwittingly helps his grandpa, Jay, with his petition. At the Pritchett-Tucker home, Gloria, Phil and Cam have formed a secret alliance to ensure their respective "mistakes" are concealed from their spouses. However, their diabolical plan may be derailed when Mitchell starts suspecting something just isn't right.

As a joke, Sheldon and Penny try an experiment designed to make participants fall in love. Meanwhile, 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.

Howard receives some shocking news as everyone prepares for the reopening of Stuart’s comic book store. Penny teaches Sheldon how to “let it go,” but can’t follow her own advice after she learns something infuriating about Amy. Also, Leonard and Raj think they spot Nathan Fillion at a restaurant.

When Sheldon becomes stuck in a rut with his work, the gang tries to help him by raising his stress levels. Howard teases Raj with a game called "Emily or Cinnamon?"

When Leonard gets minor surgery on his nose, Sheldon is the one in need of sympathy. Meanwhile, Raj's parents' impending divorce causes Howard and Bernadette to work on their own marriage.

The girls decide to re-enact their high school proms with the guys. While Sheldon feels under pressure to commit to his relationship with Amy, Howard worries about who Stuart will bring as his date.

Howard tries to distract Raj, who is anxiously awaiting data from a space probe he helped launch. Meanwhile, Sheldon and Leonard go dress shopping with Penny and Amy.

Leonard and Howard turn to Raj for help in dealing with a work emergency when they nearly come to blows after blaming each other for a potential disaster at the university. Amy throws an authentic Victorian Christmas party, while Sheldon seeks revenge on her for making him celebrate the holidays.

The Detective Boys discover the pattern of arson and manage to find the arsonist, but the final burning warehouse contains a handcuffed Takagi! Can Sato resolve a past problem relating to her father’s death and save Takagi?

Somebody is setting fires across the city! Takagi and Sato are assigned to the case, but Sato is distracted by something else. Can the Detective Boys help them solve it?