Faced with an uncertain future, Sheldon considers a major change; Emily and Raj decide to take things to the next level. Also, Howard and Bernadette struggle to care for Mrs. Wolowitz when she is injured.
A bad day compels Penny to re-evaluate her choices — including Leonard; Bernadette and Howard must care for Mrs. Wolowitz; Sheldon gives Raj advice on relationships.
After Amy ruins one of Sheldon's favorite movies – Raiders of the Lost Ark – he gets defensive, seeking revenge. Meanwhile, Leonard discovers a way to get Penny to do anything; and Raj and Stuart create online dating profiles.
Professor Proton helps Sheldon deal with grief; Leonard gets into a competition with Penny; Bernadette and Amy prepare a "Star Wars Day" gift for the guys.
When the entire gang competes in a cutthroat scavenger hunt designed by Raj that tests their science knowledge and street smarts, it brings out the best – and worst – in everyone.
Sheldon gives spontaneity a try, which causes unexpected friction for Penny, Bernadette and Amy; Raj asks Howard for help with preparation for a date with Emily.
Howard's relationship with his mother causes an unusual threat to his masculinity. Meanwhile, Leonard's friendship with Sheldon is put to the test when he returns from the North Sea earlier than expected.
Sheldon has a personal crisis when he decides string theory is a waste of his time; a double date ends in embarrassment for Howard.
While Leonard is away, Sheldon and Penny bond, but it's Sheldon's feelings that are crushed when Leonard returns from the North Sea. Also, Wolowitz helps Raj get over his ex-girlfriend.
Raj struggles with guilt when he dates two women at once; Penny has a chance to play a part in a cheesy movie; Sheldon is torn between two gaming systems.