I know if we lived in a perfect world Marvel would own the rights to all their Marvel Characters, and we would have some pretty awesome moments straight from the comic books. That moment isn't now though so the studios will do with what they have in the case of fox that is [The Fantastic Four](movie:34667) and The X-Men. There has been talks about whether or not the crossover could work or not nothing is official as of yet but here is my two cents on a story line linking the two. Lets start with the Fantastic Four reboot coming next year and this is all guessing by the way my simple predictions.
So were getting the long awaited reboot of The Fantastic Four team next year and hopefully wipes clean of the misfire that were the original two. The only things we know so far are who's playing who as well that the doombots will be making an appearance. The doombots i will get into later as they might aide in connecting the two universes. Lets go back to The Fantastic Four we know Doctor Doom will be the main villain, or maybe not? Lets pretend thought that he really is for the sake of the article. We start off with the team first learning of their superpowers in the background though we notice tidbits of the X-Men nothing too big but just little reminders that they are out there.
Then we reach our big climax as our heroes have to come to the agreement they have to band together to stop Doom and his bots he has let loose and what does Doom want you ask? The answer is quite simple domination over the world that has brought only anguish to him and to prove once and for all he is far superior to Reed Richards.
Our heroes after a giant battle that's broadcast nationwide are finally able to take Doctor Doom down though they have the chance to kill him off they decide its not the right thing to do and instead send him to a maximum security prison. The doombots are all disabled and put on lockdown at a top secret goverment base.
The Fantastic Four then together give a speech on how they will be there for anyone in need. We then zoom out to Earth where we see a flash of light in the distance and behind it galactus slowly appears smiling.
Now all of this seems pretty close to the original fantastic four films they tried doing but this would be tying in to Age of Apocalypse not really a Fantastic Four sequel. My thoughts on the [X-Men: Apocalypse](movie:1194267) is they wont take Apocalypse down the first time around, it might seem like that but i believe he will seem defeated but at the end of Age of Apocalypse he will make a deal with someone from the past.
We see a weakened Apocalypse make it past into the maximum Security prison holding Doctor Doom as he in turn asks him how much would he love to rule over all those that are against him. The Doctor with more hatred in his heart replies he would do anything just to see the world burn beneath his feet. Apocalypse laughing asks him to allow him to become his future Doom accepts and we see the two emerge as an explosion as Doom escapes and retrieves his doombots. The last scene we see is Doom staring at the camera and giving a menacing grin as he flies off with the doombots.
So there you have it my thoughts on how the X-Men and Fantastic Four could crossover thanks to apocalypse. Now the Galactus story line i think could be saved up for later movies just like Thanos is being saved up on the other marvel universe. It would make a pretty epic fight having all of the X-Men and Fantastic Four going up against Doctor Doom and his bots now fueled by apocalypse and his four horsemen in a final showdown. Thus this leading up to Galactus and his heralds. Though there are many other possibilities the studio could take if they don't have one already these are just my two cents nothing to be taken seriously of course.