Eureka Seven AO was never going to be as good as its progenitor, Eureka Seven. Very little since has been as unyieldingly brilliant as that 2005 masterpiece and few could hope to match its expansive, multifarious characters and story. That AO makes a good stab is, paradoxically, to be commended as well as lamented.

The story of Ao, a pariah on his own home island, joining up with a clandestine organisation to pilot a giant robot and battle similarly sized enemies is not new. The details of course are different and the background of political turmoil between Okinawa and Japan rumbles on while trapar - the nebulous green energy which allowed E7's robots to surf - is now mined as an energy source. For anyone with any familiarity with the original series then it's all a bit discombobulating; is this a prequel, sequel or alternate universe? Is it just another telling of the same story like the tonally wonky Pocket Full of Rainbows movie was?

The first third of the series is bashful about tipping that particular hand and it isn't until Eureka shows her face, changed now with jet black hair, that a touchstone is placed. Events trundle along and it seems a lot like a phoned in, lacklustre sequel is the best that can be hoped for. Then the Gekko Go appears. Then a pregnant Eureka appears with (another) Nirvash. Then another Nirvash appears. Then it gets weird.

Monster of the week episodics turn out to be the exception rather than the rule with a final arc that kicks off at the twelfth episode and doesn't let up until the twenty fourth. Allegiances change, people die, time is travelled and the plot twists and careens as frantically as the laser-dodging missile-chase scenes that BONES' animators do oh-so well. Some episodes are so laden with exposition though that it's a relief when something relatively minor happens like the destruction of the protagonists' headquarters.

This is not another Xam'd though whose setting and characters cried out for the long-form treatment that Eureka Seven was gifted, AO is exactly the length it was meant to be for the story it tells, however it is only half as long as its themes demand.

Like E7, AO is a coming of age tale with giant robots and alien invaders as its vehicle. Ao's fight against the enemy, whomever that may be, is really a fight for a home and for the family that he never had, complete with all the sacrifices that entails. Ao's apprehension throughout the series is rooted in his fear of irrevocably changing his world both figuratively and literally. The ending however comes too quickly so whereas Renton's triumphant cry of  "I CAN FLY" was cathartic and satisfying in the way only good stories can be, Ao's tearful denouement lacks the space to let it and the decisions which led to it, be really affecting.

Similarly the Scub does double duty as a metaphor for humanity - multiplying without end with little regard for their environment - and as immigrants angering the locals who rally against what they see as barbarians at their gates. This then is the same vein as one of the many that ran through E7: the trials of co-existence. It's handled differently here with the obvious childhood love-interest Naru forging her own path, independent of Ao, in short order. The typical harem love triangle is also broken with an empathy growing between Fleur and Ao that transcends the smutty skirt-chasing that would be standard fare.

Herein though lies the central issue of AO as a sequel: it tackles similar themes, albeit less of them, more deftly than its forebear but in the process loses the breadth and character that made its fifty one episode parent saga so compelling. There are no shades of grey, only a coruscating cerulean blue from the opening scenes of Iwato island through to the final neon pink chase through time and space. In blinding high definition the pace never settles down from full throttle with something always needing to be said, or exposed, or betrayed, or shot, or dodged, or crashed into.

Beyond its unforgiving pace though there is an awful lot to like for those willing to pick it apart. That obstinate requirement though (concentrate or else!) is enough to turn a lot of people away from it; metaphors and analogies and criss-crossing dimensions are all well and good but without a likeable or relatable core cast, for many it's all for nothing; to say nothing of the irksome dangling threads left after the final set of credits roll.

Eureka Seven AO then is a divisive series by nature and by execution. For a series that deals with time travel, its paradoxes are many, not least of which the spectre of the original series which ensures that even with Eureka and Renton's presence, without their personalities AO will always feel inferior. Even though it deals with some of the same themes and is as slick and streamlined as the futuristic Quartz Gun MacGuffin, E7's imperfection (soccer episode anyone?) made it more, rather than less, charming. There has obviously been a lot of love poured into the series, not least of which the soundtrack which is nothing less than stunning but the question one has to ask at the end of the original Eureka Seven is: "Does this need anything else? Does this need a movie or another series or is it perfect as it is?" That AO is as good as it is in the wake of such monumental parentage is astounding but, like Pocket Full of Rainbows, ultimately provides the resounding answer of no.