A missing page from Simon's journal leads Jeremiah to believe that someone at Thunder Mountain knows something they don't want anyone else to find out - and Jeremiah thinks he knows who.

Markus is planning the "summit" mentioned in the last episode, to take place in St Louis. Elizabeth came up with the idea of using the vehicles Thunder Mountain has in a relay to some of the groups to encourage them to attend.

Simon had a policy of reporting to Elizabeth every forty-eight hours while in a dangerous place such as Clarefield. Jeremiah finds a page has been carefully removed from Simon's journal in such a way as not to draw attention to its absence. Elizabeth says Lee took a look at the journal in between Simon missing a report and Jeremiah and Kurdy turning up in his Rover. Elizabeth told him that Simon had left in a hurry but she wasn't sure who he was planning to meet. When Lee gave the journal back, the last page related to the "burners" (see "To Sail Beyond the Stars").

During a search of Lee's quarters, Kurdy finds the missing page, indicating that Simon was planning to meet with the "Brothers of the Apocalypse" near Clarefield. Theo says they moved to Broxton Road there about five years ago. They take a vow of silence, and their numbers have been swelling in the past year. They gave Simon information but he died before he could get it to the Mountain (as we know). What they had discovered was that a new plague had been found that moved slower than the Big Death but was potentially even more devastating because unlike the first disease, it was affecting children and adults alike, thus potentially wiping out the human race. Evidence of this was found at one of the towns razed by the burners - the corpse of a child and a baby. The Brothers later received a message from Lee Chen to stay put and wait for further contact.

Millhaven is one of the transit points for Valhalla Sector. It is about fifty miles away from Clarefield.

This episode sees the first major rift between Jeremiah and Kurdy, as Jeremiah's zeal to find out more about Valhalla Sector puts him in direct conflict with Thunder Mountain and the only stability in their lives. When Elizabeth is shot, Kurdy takes the Rover to Clarefield to get help, leaving Jeremiah to walk to Millhaven, 48 miles away.

It seems that despite being ousted in Clarefield, Theo can move around quite freely there. Perhaps Rasmussen has come to realise that it might not be wise to make a martyr of her.

Markus has never learned to drive and says that since the Big Death he has never been more that a couple of miles from Thunder Mountain.

Ezekiel stays with the Brothers of the Apocalypse, though in what capacity we don't yet know.

Clarence is one of the Brothers of the Apocalypse. He and the rest are old enough to have been adults at the time of the Big Death.

Jeremiah: "Calm's my middle name." Kurdy: "Yeah - too bad your last name is 'before the storm'."

"When we first met, we were going the same way. But I don't believe we're going the same way any longer. So I've made my mind up. I'm going to Clarefield with you because I promised I would, and I keep my promises same as you. But after that, I'm taking the Rover and I'm going back to the Mountain. I'm going back to Elizabeth and I'm going back to some kind of purpose in my life, and that's with or without you. And if it's with, I'll come up with some kind of explanation. But after that this so-called partnership is over. You are on your own. We are done."

Theo's philosophy: "If it ain't nailed down, it's mine, and if I can pry it up, it ain't nailed down."

Markus on driving: "How can I be 'the guy' and tell people I don't know how to parallel park? It's embarrassing."

Brother Clarence to Jeremiah: "It seems your fifteen year journey is almost over."

Jeremiah's closing words: "The time for secrets is over. As of right now, everything changes. Everything."

Jeremiah tosses Markus a magic eight-ball when Erin suggests cancelling the meeting in St Louis. Markus glances at it before he says "no". A little moment, but one that makes me grin.

Someone called Nathan has been handling security for the St Louis meeting "at his end". Is this the leader of one of the other groups?

The Theo-nerd from the pilot who wasn't in "Thieves' Honor" reappears in this episode. He seems loyal to Theo.

At one point, Jeremiah murmurs "when the time is right". This phrase recurred on Babylon 5. Kurdy's response is "what the fuck kind of answer is that?" In addition, the plot of the episode has a number of parallels to the Babylon 5 episode "In the Shadow of Z'Ha'Dum", often seen as a pivotal moment in that series. Another, more minor B5 connection is in the casting of David MacCallum, who played a former teacher of Dr Franklin in the much-lambasted first episode shot for that series.

On the surface it looks like Lee is finally revealed as the enemy within when the gang discover what we knew all along - Lee is communicating with someone outside Thunder Mountain. While that suggests he's a traitor, it may turn out not to be as simplistic as that. His keeping detailed notes of Thunder Mountain operations is hardly proof that he's selling out the place; however he doesn't want the Brothers' discoveries widely known. We know he's in contact with Ezekiel, and that Ezekiel is allied to Jeremiah's father, and somehow to the Brothers; but whether Lee has personal loyalties to Jeremiah's father rather than Valhalla Sector generally still remains to be seen. Nevertheless, we do see him signal to a helicopter and asked to be picked up, saying, "my position's been compromised. You have to bring me in. Unless you want this whole operation blown wide open, you'd better bring me in. Right now."

"Decontamination procedures don't work. We have to burn the bodies", says a little girl to Kurdy. This sounds like it draws together a number of things, including the reason the burners were torching whole towns, and Captain Iron's childhood trauma of being experimented on at Valhalla Sector ( "Man of Iron, Woman Under Glass").

Several things in this series seem to have happened in Colorado about five years ago - the Brothers of Apocalypse moving to Clarefield; Andrew and his brother seeking refuge from some undisclosed trauma at Thunder Mountain; and Jeremiah possibly fathering a son. Only can only wonder if there's a connection…

(The real) St Louis is in Missouri, two states east of Colorado. The positioning of the meeting is interesting; it's roughly halfway between Thunder Mountain and the likely position of Valhalla Sector's original base. Given how much of this season has taken place near the west coast, the next US civil war could well be an east versus west instead of a north versus south one.

The Brothers of the Apocalypse are adults who were immune to the virus (rather than healthy carriers like Meaghan, judging by the non-death of people they come into contact with) and grouped together. That explains the hood and vow of silence when we met them in "Journeys End in Lovers Meeting", though they do seem a genuinely religious group. They believe the plague was a message from God that the world had become too corrupt and only the innocent - the children - were spared, plus a few adults. They believe they were spared to usher in the dawn of a new golden age - "a paradise for a thousand years". That helps explain their cryptic mission statement from "Journeys End" - to be "pallbearers for the old world - here to bear witness to the end".

Among the flashbacks in this episode is a sequence from the pilot, "The Long Road". Cleverly, a shot of what Simon sees - the dead child and baby - is inserted. In the pilot we did not get to see what Simon saw.

As the new virus is a mutated form of the previous plague, it may no longer be spread by touch. This helps explain the need for the experiments seen in "The Touch". Given that it appears to be spreading much slower, it may be spread by more intimate contact - sex, perhaps?

The absence of a "Part One" in the episode title means that the lack of resolution at the end may have come as a shock to many viewers.

Why didn't Simon take his journal with him? Perhaps the information in it was too valuable to risk falling into the hands of outsiders. In which case, why does Jeremiah always have it with him?

Is it just me, or is the time scheme of the episode a bit odd? When Jeremiah and Kurdy leave Thunder Mountain, it's light. When Erin and Markus are driving and when Lee is picked up, it's dark. When Jeremiah and Kurdy arrive at Broxton Road, it's light. When they emerge to the sound of gunfire, it's dark again. Does it take them a full day to drive from Clarefield to Broxton Road? Or did they choose to set off in the evening? If so, what were they up to all day? Also, it is said that Simon missed one of his reports, but in "The Long Road" Markus said he spoke to Simon inbetween Simon meeting and talking to Jeremiah for the first time, and Jeremiah and Kurdy turning up in his Rover, which is unlikely to have taken more than 48 hours. Perhaps his discussion with Markus was unscheduled, and it was his missing his regular chat with Elizabeth that aroused Lee's suspicion.

Where to begin? A deceptively low-key teaser is the trigger that sets in motion one of the best episodes so far, one that convincingly starts to bring together threads from the whole season while still finding time for a storyline of its own, with some moments of humour and several of great dramatic impact. Brother Clarence's revelations would be enough to make this a key episode, but as it races towards its climax, the convincing gun battle and genuinely shocking rift between Jeremiah and Kurdy make it unforgettable. Any season would be pleased to end with this good an episode, and there's still one more to come - the events of which are set up very neatly in the background of this.