Here are my ideas. I posted them in the Next trilogy thread but i didn't get many comments. What do you guys think?
Weeks after the events of X-Men 3, cured mutants are dying although a rare few seem to regaining their powers. One of the rare few to be re-empowered was Rogue and her powers have mutated and allowed her to have great measure of control with it. In the film she accepts her abilities and believes if her powers came back to her it must be a sign that it is who she must truly be.
Anyway moving more on to the plot, after finding out the effects the Cure is having upon mutants world wide the X-Men (Wolverine, Rogue, Iceman, Colossus, Shadowcat, Beast, Storm, Nightcrawler) investigate the pharmaceutical company behind the manufacture of the cure where they meet Angel who tells them that the Legacy Gene was not meant to be there; someone is trying to kill mutants. After finding out about the added Legacy gene the X-Men soon run into Sinister and his Marauders and there meeting escalates into a fight. During the fight they come to learn that this deadly touch to the Cure was added by Sinister who follows the Laws of Apocalypse. He, like his master, believes in survival of the fittest and upon hearing about the Cure he added the Legacy Gene, the deadly touch, in order to kill those who took the Cure and that his Master saw as unfit. The Marauders and Sinister escape and the X-Men return to the mansion where they digest this news and plan a course of action.
Whilst planning there course of action the X-Men are disrupted by none other than Mystique and her Sisterhood of Mutants (Psylocke, Scarlet Witch, Warbird, Phantazia, Callisto). The X-Men attack this new threat and even some of the surrounding students engage this Sisterhood. However, Mystique transforms into Jean to startle the X-Men into a standstill and explains to them that they are not here to fight the X-Men but help them. Mystique informs the X-Men that she worked for Sinister in order to get her powers back as did many of her Sisterhood and has uncovered that this Apocalypse character is not who he seems. She also adds that he is stationed at Muir Island and in order to find a cure for this Legacy Virus they must travel there. During this Callisto explains how she survived her run in with Storm; a second heart. The X-men discuss whether to trust Mystique or not and decide to head her warning and travel to Muir Island with the Sisterhood.
Upon reaching Muir Island Callisto sense something about the place
something familiar. Inside they find dead bodies and even see the helmet of Magneto lying on the floor. Mystique hopes Magneto is dead and if he isnt she will kill him herself. The X-men and Mystiques Sisterhood decide to split into 2 teams consisting of Wolverine, Mystique, Rogue, Iceman, Warbird, Beast and Scarlet Witch and Storm, Colossus, Shadowcat, Nightcrawler, Psylocke, Callisto and Phantazia. Wolverines group will go to fight Apocalypse and Storms group will defend against Sinister and his Marauders inevitable attack and look to see if anybody is till alive. Callisto argues that she should be to find Apocalypse seeing as she is the tracker but Storm says Callisto is staying where she can see her and it will only be a matter of time before the other team find Apocalypse.
Storm and her group search the facility and find only rotting bodies and ash. They soon find the Marauders but with no Sinister and engage in a fight. During the fight Callisto turns on Storm and the 2 duke it out.
Meanwhile Wolverines group are growing close where Mystique says Apocalypse lies. The X-men question her and she says knows a little girl called Layla who is never wrong. They continue to grow closer when Sinister attacks. Sinister battles them while revealing that he cannot let them kill his Master. Beast states they only want a cure to the Legacy Virus and Sinister says its the same thing. After battling for awhile longer they defeat Sinister and enter a heavily fortified room. When they enter they see Magneto and Moira chained to the floor and floating above them is a boy.
Elsewhere Storms group finish battling the Marauders and as Storm is about to finish Callisto off Callisto shouts that the real fight is happening. The Apocalypse is upon us. They run to join the other group.
Beast and Iceman go to free Moira and Mystique goes to assault Magneto when the flouting boy attacks. A brawl ensues and when Storms group enter it intensifies. During the fight he is called Apocalypse and the boy replies That foolish Sinister named me that
My name is Xavier and Xavier releases a huge mental blast. This awakens Moira and Magneto.
Whilst the fighting ensues they explain to a few of the fighters that after Charles died he entered the body of a young mutant named Proteus. But after he entered the body of Proteus he wasnt the same. He was evil. He used powers to try and destroy the Research facility but this started to deteriorate his body and he was forced to jump from mutant to mutant. Why he kept themselves alive, Moira and Eric did not know but they do know that he was found by Sinister. Sinister mistook Xavier for a God and planned to restore Xavier. He used the DNA of Proteus and used it as the Legacy Virus. Proteus DNA was spread round the world and drained mutants of their power and giving it to Xavier. They tell them that they only way to kill him is to leave him bodiless. Storm says she cant kill the Professor but Moira explains it isnt Xavier anymore its a monster.
The X-Men, the Sisterhood and Magneto battle it out and eventually destroy Proteus body. They are heavily injured and return to the mansion to recuperate. The ending of the film is the twitching of Sinisters hand.