Peter Bishop is back. Joshua Jackson made his season four return to Fringe last Friday, on an episode that left our critic with many questions. Where does the how go from here?

To one of our favorite character actors: Stephen Root guest stars on next week's installment, "And Those We've Left Behind." The former Newsradio/Justified/True Blood star will appear as an electrical engineer who, along with his wife, helps the team during a search for a pattern between time-loop anomalies.

Watch the official Fox preview now:

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