What brings Sage back to Mystic Falls? Who is this mentor's one true love? How will she team up with Damon? And what does medical science have to say about the unusual condition of Alaric Saltzman?

All these questions and more are both answered and teased by Vampire Diaries producer Julie Plec in the following video preview.

Get an idea of what's to come this week on "Break on Through" now:

For more episode-related spoilers, check out:

• These photos from the installment.
• This TVD clip.
• The official CW preview.

Matt Richenthal is the Editor in Chief of TV Fanatic. Follow him on Twitter and on Google+.