As previous Fringe spoilers have revealed, this Thursday marks a significant episode of show lore.

Courtesy of Walter, Olivia will go back to her alternate reality, where she'll recall events from the May finale and, once again, comes across the mysterious William Bell.

Check out the official Fox preview for "Momentum Deferred" below:

[video url="http://www.tvfanatic.com/videos/promo-for-momentum-deferred/" title="Promo for Momentum Deferred"] [/video]

We've posted a couple pics from this episode already, but click on the images below for a complete preview of scenes to come this week:

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