Ergo Proxy has one of those title sequences I've grown to love. A blend of animation and colourised live action, infused with a dose of MTV stylistics and the opening titles for Se7en and set to a terrific Monoral track, it's effective in itself, but like that wacko opening for Paranoia Agent has come to mean one thing above all else – I'm about to watch a new episode from this compelling anime series, and that alone is cause for a frisson of excitement. And now the stakes are upped, as here Ergo Proxy delivers on the considerable promise of its first eight episodes and takes the sort of chances with character, story and pacing that mark Volume 3 as the best yet and suggest that what was until now a very fine series might just be in line for greatness.

It's almost a given that you don't try dropping into any series three volumes in, but this is truer of Ergo Proxy that any other show I can currently call to mind. Recently, I was sent Series 4 of the comedy Peep Show for review and managed to work out what was going on and get a hold on the back stories without too much trouble. But Ergo Proxy? Forget it. Even if you've been following the series avidly, the four episodes here are still likely to have you scratching your head a bit. Newcomers won't stand a chance. If you do fancy taking a look – and you should – then get Volume 1 and Volume 2 under your belt first. Everything that follows assumes you've done that. If not then you've been warned, as there are Volume 1 and 2 spoilers ahead and without that preparation there's a good chance none of this will make much sense. There are also a couple of spoilers from this volume, necessary to discuss the episodes in anything deeper than a superficial "it's very good" level. If you want to go in cold then skip to the summary.

Volume 2 ended on a dramatic note, the sort that weekly serials used to specialise in, and in their deceptive spirit there was a bit of a cheat going on here, one that few series regulars will have been fooled by. After all, you don't build all your publicity artwork around a character who's going to be killed off in episode 8 of a 23-part series, especially one that male anime fans have the hots for. Teasingly, we're made to wait a full episode to confirm this and then not supplied with the specifics. Not that it really matters – Re-l was, after all, shot in the presence of the androgynous Dr. Daedalus, who is no doubt skilled in all the necessary methods of humanoid repair. The key plot point here is that (almost) everyone else believes she's dead, enabling her to work secretly with Daedalus to locate another proxy in the vast areas outside of the domed city of Romdo.

Ergo Proxy, Volume 4 sees the philosophical elements that have run through the series from episode 1 moved to centre stage, as both Vincent and Re-l struggle to comprehend the nature of their respective true selves. Vincent and Pino have been rescued by a man named Kazkis Hauer, who after treating them as his guests begins pushing Vincent to recall his forgotten past. The overt suggestion is that he is a proxy, something we've all suspected for some time now, but also that while in Proxy form he killed his former partner Senex, someone Vincent now has no recollection of. Hauer is clearly not to be trusted, and even when he's being genial he doesn't fool Pino, whose fear of her surroundings signals her continued viral development from AutoReiv to human.

Back in Romdo, Dr. Daedalus is approached by Security Bureau chief Raul Creed, who re-instates his licence to practice but ensures that the doctor will work exclusively for him. Daedalus capitulates but clearly has other plans and appears to have developed something of a thing for Re-l. Haven't we all? Re-l, meanwhile, finds herself in a deserted suburban community that has been perfectly preserved by an army of droids designed specifically for that purpose. The people have long gone, but no-one thought to shut down the machines that clean the houses and tend to the parks. Her search for a proxy is unsuccessful, but she does find a small child of playful disposition who wants to play with her "together from now on" and who then talks to her in a manner far beyond her years. Is it a dream, a vision? Or has Re-l been put in touch with her inner child, her lost youth? Repeatedly there is the vocal suggestion that characters have lost their raison d'être, and this is not some creative subtitle translation but a term used even on the Japanese track.

This metaphysical drift reaches a peak in episode 11, Anamnesis, in which Vincent stumbles on an isolated bookshop in a mist-shrouded location with shades of of the video game Silent Hill, where his reality suffers a deliciously disorientating temporal and spatial collapse. Under the control of an ageing proprietor who may or may not exist, he is brought face to face with multiple images of his own proxy, with whom he engages in philosophical discussions on the nature of the self and specifically his self, propelling him towards his pre-Romdo location of the Mosk Dome for answers. We're back on surer narrative ground for the final episode of this quartet, Hideout, but concrete answers are not forthcoming, and as the episode ends there are a number of questions left intriguingly dangling for possible later clarification.

As ever, the dark sense of unease is enhanced by some stylish artwork that all but rejects the typical animation fondness for bright colours and high contrast, and an extraordinary soundtrack layered with Blade Runner-esque sinister hums, dreamy harmonies and semi-abstract chords and notes. With the action reduced to a minimum, this is animation for the intellect rather than the adrenal gland, and a compelling example of why anime of this calibre demands to be taken as seriously as live-action drama, a form that can only dream of indulging in the sort of mesmerising devotion to atmosphere over action, complex philosophising and rich and fragmented character introspection that is Volume 3 of Ergo Proxy.

The four episodes contained on this volume run 9-12 and are: Angel's Share, Cytopropism, Anamnesis and Hideout.

Again the 1.78:1 anamorphic transfer is a good one, and it needs to be given the dark look and use of gloomy greys and browns that has become the series norm, so much so that occasional jaunts to brighter landscapes come almost as a jolt. There are no obvious conversion issues or compression artefacts anywhere.

The usual three soundtracks are on offer: Japanese 5.1, English 5.1 and English DTS and there's precious little to choose between them. All are wonderfully atmospheric, with very good separation and surround work and the distant, dreamlike score making for a very immersive aural experience.

As someone who always prefers the original Japanese voice track I have to say that the English one here is pretty good, although for my money the voice best suited to the character is Liam O'Brien's Vincent Law.

None really, just trailers for Ah! My Goddess (1:32) and Black Cat (1:31).

In Volume 3, Ergo Proxy really comes together in challenging and imaginative fashion, although in a manner that will probably irritate the action anime fans. Watching the four episodes here is at times an almost hallucinatory experience, and one that feels very effectively self-contained, a similarly styled quartet whose conclusion feels like the end of a chapter. If you've been following the series then this volume comes highly recommended, if not then it really is time you gave it a look.