Alex Ball

Sheldon and Penny bond in Leonard's absence, and Koothrappali finds someone to share his heartache with. Elsewhere, while away at an out-of-town conference, Bernadette and Amy are hit on at the hotel bar.

Love is in the air when Amy convinces Sheldon to join her, as well as Howard and Bernadette, for a romantic train trip to Napa Valley to celebrate Valentine's Day.

Rachel goes to a job interview at a restaurant and winds up sitting next to her current boss; Joey feels abandoned because Monica and Chandler are leaving.

Russell discovers the series of benefits of having a male assistant by his side. Plus, Audrey makes a bet that she can commit to finishing an important project.

Jeff wants different stories to share with Russell and Adam, and so he comes to Audrey about creativity in the bedroom. Meanwhile, Russell realises he knows nothing about his date.

McGee and Bishop head to Afghanistan when a local case is connected to a series of friendly fire deaths overseas. Kasie ventures out of the lab and joins Torres in the field to analyse additional forensic evidence.