The last arc-heavy episode prior to the big bang of Chrysalis, this episode answers a few questions posed in earlier episodes while at the same time opening up some big new ones.
Ivanova monitors some bizarre tachyon emissions coming from the point in space where the Babylon 4 station disappeared four years earlier. She dispatches a ship to investigate. When the ship returns, its pilot is dead... of old age.
Shortly thereafter, Sinclair answers a distress call from that location: a call identified as coming from Babylon 4. He and Garibaldi lead a rescue mission to evacuate the 1200 - 1300 people trapped aboard the station. When they arrive, they make several discoveries. The first is an alien named Zathras who insists that the station is being taken out of its original time because it is needed to fight a great war. The next discovery is that the time distortion effects everyone aboard, giving Sinclair a flash of a future in which he and Garibaldi are fighting an unstoppable alien force, and giving Garibaldi a flash of his breakup with Lise.
Meanwhile, Delenn is called before the Gray Council for a great honor. She has been elected to replace Dukhat as leader. "You must be relieved," one of her colleagues tells her, "to know that you will never see Babylon 5 again."
Since we are now very near the end of the first season, this episode seems a good time to note two of the things I will miss when Sinclair leaves. One is the sheer screen chemistry that exists between Michael O'Hare and Jerry Doyle. Doyle's preference for working with Boxleitner is a matter of record; but, in my opinion, Jerry Doyle has more natural screen rapport with O'Hare in Season One than he has with anyone except arguably Andreas Katsulas in the rest of the series. On-screen, these two just seem very natural as friends. Scenes such as the precredit sequence or the "fasten/zip" scene on the shuttle really highlight this, and when O'Hare leaves the rapport between these two will be a great loss to the show.
Another aspect of O'Hare's performance that these scenes highlight is a surprising one, given both the actor's general stiffness (even when he's at his best, he does carry himself a bit stiffly) and the serious nature of the character. This is O'Hare's startling knack for comedy. I've been reminded of this knack several times in the last few episodes. The facial reaction he and Claudia Christian give at the end of Eyes, as they watch Garibaldi on the motorcycle; the smile that slowly falls into a frown when he sees Garibaldi in the lift in the opening of A Voice in the Wilderness (punctuated by his wonderful delivery of "I think I'll join you," when Talia decides to take the stairs); and his very funny interaction with both Garibaldi and Ivanova at the mess table in the precredit sequence of this episode. It seems at odds with just about everything else in his performance, both his other strong points and his weak points, but O'Hare is very, very good at a particular kind of comedy. Best to mention it here, since I don't think many opportunities for him to play comedy arise in the rest of the series.
As to the episode itself, it is a justly-praised one, certainly one of the first season's highlights. By this point, near the end of the season, the show really does have some strong momentum going, and this episode cranks it up a notch further.
Ever since The Gathering, the show had poised several questions to viewers. One of the most intriguing among these was the question of what happened to Babylon 4. This episode answers that question: Babylon 4 was taken to another time in order to be used for a base operations in fighting a great war.
But the answers open up even more questions. Was Babylon 4 taken forward in time or back? Who is Zathras, and who is this "One" he speaks of serving? The last is answered (at least in part) at the very end of the episode, when we see an aged Sinclair revealed as "The One." But this opens even more, and more interesting questions. The Sinclair we see is very old; how far in the future has he come from? Where/when is he taking the station, and who does he intend to fight? Why is Delenn with him, and why does her manner toward him seem so much more familiar than the Delenn we see in the show's present? And what exactly is it that he "tried to warn them" about?
To the show's credit, most of these questions end up being rather nicely answered by Season 3's War Without End. A few of the questions are slightly obsfucated, of course, and a couple of other elements are dropped (famously, Delenn's hand and arm touching Old Sinclair at the end), largely as a result of changes to the series between this episode and that one.
One could speculate that the flash-forward we see of a half-crazed Garibaldi furiously battling an alien invasion force on Babylon 5 is one that was originally intended to happen within the series, and that this was changed later. I suspect this was the case. But Signs & Portents already gave the show a "get-out" clause for this and other changes when Ladira told Sinclair that "the future is always changing" and that any prediction was only of a possible future.
Certainly, the episode itself plays very well, enticing first-time viewers with broad hints of things to come. It also holds up when viewed after the fact. Despite a couple of elements that ultimately were not able to fit (both due to time constraints and to changes in the series), it achieves its narrative purpose within the story... and when looked back on after seeing the full story, it still holds up. A definite achievement, marvelously structured by a writer/producer who was in total control of his vision.
Oh, and one other little thing that only becomes clear after seeing War Without End: this episode marks our first glimpse of John Sheridan (though presumably, the figure would have been either Sinclair or Delenn in the original plan). And Zathras' single line delivered to him (second-time viewers will spot it instantly) actually fits perfectly with events in War Without End. An entertaining thing to spot, in retrospect.
No real bad within the episode itself (although a few of the minor characters on B4 are a bit shakily acted). A few niggles where this episode and Season 3's War Without End don't quite match up... but I'll discuss those in more detail when I get there.
It doesn't pack quite the emotional punch that some of the other episodes this season have done, but the overall construction is so well-done and well-structured that I can't give this episode anything but full marks.