Guest Appearances

When Raj is cut off from his father's fortune, he appoints Sheldon in charge of his finances to help him get out of debt. Meanwhile, Penny considers joining Leonard at Comic-Con.

Leonard, Penny and Raj adjust to their new living arrangement, while Sheldon takes an interest in Amy's work.

Penny helps Sheldon figure out his next scientific move.

Sheldon plans a special themed dinner for Amy's birthday.

Sheldon wants to experiment on Howard's kids.

Howard dresses up as Sheldon for Halloween.

This holiday season, the Parkers discover that romance isn't always a smooth ride as Matt and Eve are on thin ice; Gabe enlists Riley to help Amelie impress his mum; Carter seeks help with his promposal.

Hank and Karen throw a dinner party for a few friends. Before everyone arrives, Hank pops the question, but Karen begs off to think it over. At dinner, it's revealed that Hank is the likely father of Sonja's baby, and Ashby nearly dies of an allergic reaction to sushi.

Randall reflects on what could have been.