If you haven't read the full "Story of Sarah Jane", then first read Part One, Part Two, and Part Three. Here's Part Four from the official Doctor Who site.
Sarah Jane is about to meet the Eleventh Doctor, in the forthcoming episode, Death of the Doctor. She's weaved in and out of the Time Lord's travels for decades, sharing his battles and appetite for adventure. But now she's aware that life beyond the TARDIS can be as exhilarating - and as eye-opening - as any voyage to Venus or beyond.