David Trice

While Sheldon and Koothrappali attend a university mixer, Leonard is upset to discover that Penny believes in psychics. Danica McKellar (The Wonder Years) guest stars as the object of Raj’s attraction.

When the girls' trip to Vegas falls through, the guys invite them to play Dungeons & Dragons – causing Sheldon and Amy's relationship to take an unexpected turn. Meanwhile, Raj and Lucy go on a very awkward date.

When an 8-year-old is found dead on the Appalachian Trail, the team searches the forests for a man targeting children.

The team searches for a bomber who set off an explosion at a small town school.

Randall adjusts to the foster system. Kate and Toby take the next step in their relationship. Kevin visits Sophie in New York. Jack and Rebecca finalize Randall's adoption.