After the dramatic ending of the previous DVD left Ayato stunned and grieving, events in Terra proceed without him. Isshki, the Bahbem Institute's observer, takes over command, to everyone's chagrin. He quickly earns the title of 'White Snake,' convincing Haruka to cooperate with him, and even threatening Ayato with execution. Mysteriously, Reika (Ixtli's human form) shows up at the command center in uniform as an alternate Haruka with an agenda of her own - to start the beginning of the end.
But Reika/Ixtli's efforts to initiate the tuning of the world is by no means the only crisis that is building - Mamoru, who knows that Ayato caused the death of his girlfriend appears. He takes advantage of Ayato's guilt over Hiroko to gain the opportunity for revenge and to carry out the Mulian agenda of destroying the island of Hirai-Kanai.
Isshki is intent on bringing down the Jupiter barrier, regardless of the effect of freeing the Mu, expecting to win the ensuing battle. But by using an ingenious reversal, the plot manages to turn things upside down, trigger a world crisis, and make Ayato take steps toward assuming the instrumentality he has been desperately avoiding - all without ending the series four episodes too early.
If it sounds like a lot is happening in a short period of time, that is the case. Overall, the pace of this series has been fairly steady, but the directors are now trying to make up for lost time and build up steam for the conclusion. And they do a good job of it.
The subtle otherworldliness that is created by using Aztec and Nahuatl symbols and names becomes much more blatent in these episodes. This ranges from Reika/Ixtli's declaration "I am but the true face" (Ixtli is the Nahuatl word for face) to the appearance of Aztec sculpture and symbols. However, this never quite makes it to being a plot device, working more like the Kabbalistic symbolism in Evangelion, the series to which RahXephon is most often compared. It adds mystery, and an alien seeming terminology, but doesn't ever rise to being a cause or explanation for what the viewer is seeing.
While RahXephon will go throughout it's life being compared to Evangelion, this is unfair to both efforts. While there are similarities both in plot and theme, they really are each truly unique. In addition, RahXephon's commitment to strong artwork and music are outstanding, while Evangelion's animation shows better choreography and use of film angles. both series get high marks for acting. Personally, I'm delighted to have each of them on my shelves as examples of anime at it's finest.