The result is a fun, fast-paced piece of work that - while it doesn't feel like it's completely necessary as a bridge between "Messiah Complex" and "Second Coming" in the Hope Trilogy - is the best example you're going to find of what life was like for Cable and Hope between those events.
X-Force - Cyclops' personal private hit squad made up of leader Wolverine, original generation members Domino and Warpath, the bipolar Angel/Archangel, young healer Elixer, shady villain Vanisher and teen girl Wolverine clone X-23 - is sent into the far future to track down Cable and Hope, who are only able to move forward in time by their own means. The setting: a time ruled by Cable's psychotic clone, Stryfe. The team finds Cable and the girl, but is unable to bring them back to the present. Before you know it, Hope has been abducted.
I have never been a big fan of Cable. I like the character as a piece but never as the whole. His most interesting relationships - including with his mother and father - are rarely touched upon, while the ones that get the most focus - involving the likes of Domino and Cannonball - really never go anywhere. Hope changes that to a degree. While the idea of an old, grizzled soldier protecting a young girl has been done to death, it's something that society never really gets tired of. His concern for her well-being is well-depicted and the positive influence over his adopted daughter shows growth. That said, Hope is still a little girl and her ending up in the hands of Bishop - who wants to kill her - and Stryfe - who would exploit her - is damn fine motivation for our band of heroes.
While "Messiah War" is fairly straightforward, it throws in a few key twists. First is the presence of Apocalypse, who is shuttered off to the side. He calls Archangel to his aid, leading to a crisis of morality AND identity for Warren. Their confrontation is powerful. The other curve ball: Deadpool. A future version of Wade (or so it seems) is working for Stryfe and is really on point here. Craig Kyle, Christopher Yost and Duane Swierczynski use him perfectly. The story of how he ended up in the future is pure gold, and Wade is really made to look like a spineless slimeball. It's actually amazing that - given how Apocalypse and Deadpool are in this - they find ways to be effective without being dominant.
That's important because I consider the best part of "Messiah War" to be the interaction between the two villains, Bishop and Stryfe. Bishop has gone completely off his nut, murdering people by the millions because he expects his acts to be erased once Hope is killed. While he recruits Stryfe for help, Lucas has to keep his cards close to his chest or else Stryfe will claim her as his own. What doesn't help matters for the heroes is how Stryfe and Cable share the same face. Hope mistaking the clone for the original is chilling and Stryfe plays his role to perfection. It leads to a great smash-up with a hell of an ending, though ultimately everything ends up right back where it started - except now the X-Men know Cable and Hope are still alive.
"Messiah War" is the part of the Hope Trilogy you can afford to skip. It adds to the overall arc in some ways, but none of them vital. It is still quite good, but parts one and three are miles ahead.