The gang is thrown for a loop when Leonard gets offered a great job overseas on the season finale of The Big Bang Theory. "The Bon Voyage Reaction is the 24th episode of the show's sixth season.
Added:

The Big Bang Theory Season 6 Episode 24 Quotes

Who do you think would win in a fight -- you or a shark?

Sheldon

Leonard: I know what you are doing. You don't want me going on this research trip because you're afraid to be alone.
Sheldon: I'm not afraid to be alone. On the sea, it would be terrifying. Because of all the drowning.