Sheldon goes to Vegas to win money for science. Also, Penny and Bernadette take Amy wedding dress shopping, but her terrible choice entangles them in a web of lies.

Amy and Sheldon's wedding provides Sheldon with the information he needs to make a breakthrough in his symmetrical string theory. Meanwhile, their friends pick up Sheldon and Amy's families from the airport, and Mark Hamill agrees to officiate at the ceremony.