If you're like us, you can't sleep waiting for the big two-part season finale of Fox's Fringe, "Over There," in which Olivia and Walter go to the other side; check out the extended preview below. (Spoilers ahead!)

The alternate universe is revealed in "Over There," which airs Thursday at 9 p.m. ET/PT and concludes the following Thursday, May 20.

Look closely and you'll get a glimpse of the alternate versions of our favorite characters, as well as a first look at the return of William Bell, played once again by Leonard Nimoy.