When Charlie meets the fiancée of Angie's grown-up son, he realizes it's not for the first time. Alan tries to get Jake to study for his algebra final.
Penny's break-up spurs Leonard to summon the courage to ask her out, and each goes to Sheldon for advice on their upcoming date.
Charlie's attracted to an older self-help author. Alan's insistance that Jake complete his Taming of the Shrew book report is hampered by Jake's continually losing the book.
Penny wants to throw a surprise party for Leonard, but Sheldon's indulgence at an electronics store throws her off-track.
Jack moves on to a new job at Homeland Security, but the position is not quite what he anticipated. Meanwhile, Liz suffers a pregnancy scare, Kenneth confronts rival page Donny when applying for a Beijing Olympics gig, and Tracy works on his latest invention.
The rest of the gang fall for Sheldon's twin sister, and Leonard's plan to win her heart is derailed when Sheldon declares he'll be the one to decide who can date her.
Robbie takes Miley and Jackson to a cafe that has special meaning to him, but they don't share his love for reminiscing. Oliver and Lilly find themselves in a sticky situation.
Floyd stays at Liz's place overnight when his flight is canceled. Meanwhile, Jack is demoted to the 12th floor, causing him to question his future status at the company. Finally, the staff celebrates Annual Sandwich Day with mysterious sandwiches from a secret location in Brooklyn.
