One of the main complaints that I (and, well, pretty much everyone who read it) had about the "Age of Ultron" event was that the pacing was totally bizarre. First, we didn't wind up seeing Ultron until the last issue. Second, the characters spent so much time jumping from era to era that it was hard to tell who was doing what, when and why. Conversely, the X-scribes have really done a spectacular job of hitting their marks in this event. Aaron brings us to the point that we all knew that we had to reach, with original Jean learning of her future from future Jean, who we learn is actually future-original Jean and not future-present Jean.
(As confusing as it sounds, it actually makes sense. I had mentioned previously that we had to learn, at some point, how original Jean traveling into the present changed her future, given the assumption that her advanced powers meant that Professor X wouldn't be able to simply erase all repercussion of their "visit" with a timely mind-wipe. Events so far imply that original Scott maintains a connection to present Scott -- given the latter's disappearance as a result of the former's death -- but it's unclear what connection original Jean maintains with present - a.k.a. dead - Jean. In other words, original Jean hasn't done something that suddenly resurrects present Jean, as far as we know; her connection is only to future Jean. It implies that the repercussions of their travel are so far constrained, since nothing in the present - except for Scott's brief disappearance - has changed. Future-original Jean is a creation of the new timeline created when original Jean came into the present; she's not the result of a change to present - a.k.a. dead - Jean. But, again, it's unclear how long we can expect that these events not affecting the present will be the case.)
As a result of the horrible future that she sees in her future self's mind, original Jean decides that she and the other original X-Men have to return to their past. However, it's here where the X-scribes cleverly more us to the next phase of this event, exploring original Jean's suspicions that these X-Men aren't who they say that they are. Magik takes original Bobby and Hank with her to the future X-Men's future (after having caught a glimpse of it on a previous trip) and they discover Sentinels subservient to another group of future X-Men occupying the Jean Grey School. As such, it's clear that the original future X-Men are somehow vying against the new future X-Men. However, we have to assume that it's not over something trivial; after all, future Jean was essentially willing to lose her life to prevent this future from occurring. As such, if it's not all Ahabs and hounds, what is it that so terrifies the original future X-Men?
(Honestly, as much as I'm enjoying this series, I pretty much have to call it quits with this review at this point, under the weight of too many "future-original Jeans" and "new future X-Mens." Oi vey.)