In many respects, the first season of Fringe has been just as mercurial as many of the characters that inhabit it. When it's been on form it's been excellent and intriguing, and at its low points it's been something of an X-Files pretender.

While alluded to early on, the larger story arc about the alternate dimension has been woven subtly into the individual narratives. But the final story, There's More Than One Of Everything, is entirely about The Observer, the other dimension and Dr. Jones' attempts to get there.

It starts where the previous episode ended, with Nina Sharp who'd been shot. She's not dead due to her modified physiology. This wasn't a revenge attack or a random incident; those that attacked her wanted something hidden in her artificial arm, which they took. It appears to be the ultimate Duracell, and the strangely mutant Doctor Jones took it to power a device that can open a door to the alternate dimension.

He keeps cropping up at various points across the Northern seaboard of the US, in places we're later told are ‘soft spots' between our dimension and this other alternate one. His first attempt results in a truck cut in half, his second does much the same to a soccer player; the technology clearly isn't entirely predictable.

Meanwhile, Walter had gone walkabout with The Observer, and we see them in a number of locations including at a grave. To help Walter remember what he's looking for, The Observer gives him a coin, and explains that it isn't the ‘original' as there is always...two of everything. Quite what this precisely means is only revealed towards the end, although it obviously relates to the two dimensions.

Concerned for his wellbeing, the FBI is looking for Walter, and Nina Sharp soon comes along with some useful intelligence as to where he might have gone. Peter uses this information to travel to a beach property that he and Walter went to when he was a child. Walter is already there, but he doesn't even know what he's looking for. Eventually, their conversation unlocks Walter's memories and he locates a metal box on which is an identical coin to the one he was given.

Inside is a device Walter and William Bell made to plug a dimensional door, exactly the one that Dr. Jones is so desperate to open.

Walter and Peter then head to where they expect Jones to try again, to which Olivia, by an entirely different route, is also heading. They arrive as Jones opens a portal and heads to go through it. He's shot multiple times by Olivia, but the matter-transport escape he made from the prison appears to have made him immune to bullets. He's stepping through when Peter uses the plug, cutting him in half, which he isn't resistant to.

Then we get the full explanation of the title, and a stunning revelation. Walter goes back to the grave, where we see him crying. He places the coin on the top of the gravestone and the viewpoint shows the grave is Peter's, and he died in 1985, aged 8. Oops.

The Peter we know is therefore probably from the other dimension. Is Olivia also? Questions for season 2, I'd suggest.

The final scene is a lovely set-up for that second season. Olivia Dunham goes to meet Nina Sharp, but she doesn't show up. She goes to leave and steps into the elevator. As it descends there is a flash of light and for a moment she sees other people in the elevator with her. When the doors open, a woman leads Olivia into an office, where William Bell arrives shortly afterwards.

When Bell emerges from the shadows, the J.J. Abrams/Star Trek/Fringe connection is complete, as it's Leonard Nimoy, looking very well for his age. What I liked about this brief appearance was that Nimoy was revealed bearing a broad smile, in an obvious, but possibly necessary, 'this-isn't-Spock' statement. He only has a couple of lines, and then we get the pull-back from the building they're now in, which certainly isn't the one Olivia started out in. I know that because the one she's in now doesn't exist in our world, as it's the World Trade Center.

Nice ending, even if the idea of that particular shock was actually used previously by Life On Mars in its first episode last year.

The season certainly went out with a bang, and I'm now looking forward to the next one with some anticipation.

Check out our review of episode 19 here.