Walter's challenges are just beginning, judging from tomorrow's Fringe episodeS

We've seen tomorrow night's all-new episode of Fringe, and we're happy to say the show's continuing its winning streak. John Noble is still bringing the finest comic timing and raw pain to television, and Anna Torv's never been better.

Here's our spoiler-free preview post of tomorrow night's episode, "The Firefly."

Without giving anything away, this episode picks up where the first half of the season left off. Olivia is still dealing with the knowledge that while she was trapped in another universe, Peter was romancing the "other" Olivia. Walter is coping with the guilt of knowing just how much damage he caused when he brought Peter over from the other universe, and Peter is still blaming Walter a little bit. And the threat that Peter might be sacrificed in some sort of mysterious doomsday machine is still hanging over everybody's heads.

But tomorrow night's episode manages to find ways to deepen a lot of the show's themes — and we continue seeing the show's moment of original sin, Walter's visit to the other universe in 1985, from new angles that shed more light on it. Just when you think Walter can't feel worse about what his selfishness caused, the show finds a new way to torture him yet again — but at the same time, the idea that Walter could find redemption and help undo the damage he's caused is also dangled, more tantalizing than ever — but the cost may be too high for him to pay.

Walter's challenges are just beginning, judging from tomorrow's Fringe episodeS

It's really impossible to do tribute to the acting of John Noble in words — I hadn't watched Fringe in a month or two, so I was gobsmacked all over again by just how good he is in this new episode. Really, even if you don't understand all the backstory about alternate universes and doomsday devices, you only have to watch Walter struggling with his past and with his desire to save his son one more time, and you'll be completely sucked in. At its heart, this show is really a great father-son story, and this episode reminds us of that fact from the very first scene. In this episode, in particular, Noble does an amazing job of flipping between childlike humor and weight-of-the-world darkness in the same scene — some of Walter's silliest, craziest ideas turn out to be motivated by the constant, gnawing awareness that he's running out of time to avert another tragedy.

It's not really a spoiler to reveal that Cristopher Lloyd, aka Doc Brown from the Back to the Future movies, is in this episode, and he's completely amazing as a burned-out old rock musician who played in Walter Bishop's favorite band. The two great character actors bounce off each other wonderfully.

Walter's challenges are just beginning, judging from tomorrow's Fringe episodeS

And I have to give another shout-out to Anna Torv, who shows Olivia putting on a brave face but utterly dying inside as she contemplates everything her doppleganger stole from her — all of the conversations Peter had with the other Olivia instead of her, all of the stuff they shared. For someone who has the massive intimacy issues that Olivia has, knowing about Peter and Fauxlivia must feel like an even greater, more insurmountable barrier to intimacy — to achieve any closeness with Peter, she would have to find a way to repeat what the other Olivia other did, and you can see her grappling with the idea.

There are some bombshells in the episode, including some shocking revelations that I won't give away here. But honestly, what you'll remember after watching this episode is what you always remember after the best Fringe episodes — the little character moments, the ludicrous Walter experiments and the instants when you glimpse the outlines of a saga that's huge but manages, simultaneously, to be a small story about three damaged people.

Cancel your Friday night plans — this one's worth it.

Screencaps via FringeFiles.com