The Statue of Liberty...is now ruined. In the dark future of 2055, New York is now a run down city. We see Wolverine and two other mutants on the run as they are being chased by two Sentinels, who are flying around the city with a single purpose: the eradication of all mutants.
The mutant trio manage to take out the Sentinels but Wolverine says that he must be getting rusty, he used to be able to destroy them quicker. Someone else shouts out that he agrees and they turn around to see someone on a vehicle looking at them.
It's Bishop, a "tracker" who hunts down mutants for a reward. He takes down all three of his targets quickly and puts them in his vehicle. When Wolverine wakes up, he sees that they are on the move and that touching the net isn't a good idea.
Bishop is taking the three to a mutant termination center. Wolverine has heard of him and knows that Bishop is a mutant himself. He tries to convince Bishop that the Sentinels want all mutants dead, but Bishop says only the ones that cause trouble -the ones that go around attacking Sentinels -are going to die. They soon arrive and Bishop shows his I.D. and asks where his reward is at. The Sentinels scan his card and see that his bounty quota has been reached, they tell him that he isn't needed any more!
So Bishop gets made to carry one of the other mutants as he is also marched into the termination center. Wolverine asks him what he thinks of the Sentinel's retirement policy, which doesn't do down well. They then come across a depressing site -the graves of the legendary X-Men. The Sentinel with them tells them to keep moving, but then one of the other mutants blasts the robot with an electricity blast.
Wolverine gets hit but Bishop displays his energy blasting powers to help him out and take down the Sentinel for good. The mutants had a mission to complete however so Wolverine is given something by one of the other mutants and then he and Bishop head off. Early on in the morning the pair arrive at their destination and knock on the door.
They are greeted by Forge, the leader of the rebel mutants. He takes the cylinder Wolverine had and puts it into a machine, which powers up. Bishop finds out that the rebels have a working time portal!
Forge has also constructed a temporal transceiver -a watch like device which allows the wearer to set what time they want to travel to when they go into the time portal. Forge explains to Bishop that Wolverine is going to go back to the 1990's to prevent an assassination from taking place. They have a theory that if this certain assassination doesn't happen, the bad future they live in won't happen either -meaning no Sentinels, no mutant termination camps etc. But Bishop knows about this assassination and he knows who the assassin is -surely Wolverine won't be able to kill him? Wolverine says he knows what must be done and that when he goes through the portal they should destroy it to stop anyone or anything else from getting through, even though it means he can't return, either.
Bishop says that Wolverine won't be going -he will be instead, and he takes the transceiver. Wolverine doesn't like it but Forge says he's right, as Bishop is younger and he bested Wolverine earlier. The place then comes under attack from the Sentinels so they have to make a move now. Forge tells Bishop that the transceiver has all the information he needs on it. The Sentinels begin to rip the building apart so Bishop leaps into the time portal. As he leaps into it he hears laser fire and turns around to see Wolverine dead at the feet of Nimrod, an advanced Sentinel unit!
But then he starts to travel through time and suddenly finds himself on his back in an alleyway. At first he thinks the time portal hasn't worked as the place he's in now is run down but then he sees something...children...on the street? In daylight?! He watches them run off and realises that he really has gone back through time after all, but an after-effect is that he just can't remember why he was sent back.
He goes past some newspapers and sees the date, confirming that he definitely has time traveled. He sees the cover story on the paper: Professor Charles Xavier is giving a speech today...he recognises the name, but he just doesn't know if he came back to do something for Xavier or not. Was he meant to kill him? He doesn't remember. Meanwhile, Rogue and Gambit are visiting Beast. Gambit can't understand how Beast could want to be in this cell and wants to free him, but Beast says no because he still wants to go through with his trial. Beast shows us how Gambit and Rogue got in the cell in the first place as he makes an exit for them.
Meanwhile Bishop is using the transceiver to try and find out information on what's he meant to be doing here and comes across details on the X-Men. He hears two kids running and they are excited about the new video game they've just got, called Assassin. This clicks with Bishop who now remembers he came back to prevent an assassination, but he also says that the X-Men are the assassins!
Now he knows what he has to do, Bishop's next stop is the Xavier institute. He takes command of a bus and heads toward there, but as he crashes down the gate Jubilee raises the alarm and soon the other X-Men get ready to fight.
But Bishop is going too fast and before the X-Men can get outside, he crashes through the front door and then gets out of the bus. He then shoots down Storm and Cyclops before losing his weapon thanks to Jubilee shooting it out of his hands.
More of the X-Men arrive and Wolverine takes the intruder down. Bishop remembers Wolverine and tells him to stop, but forgets that the Wolverine fighting him now won't know who he is. He tells them all that he has come back here to save his future. The Professor then arrives and stops Wolverine from killing Bishop so they can instead try and find out who he is and why he is here. Bishop complies and so Xavier mind-links with him with Cerebro.
The images the Professor can see are displayed on a screen. He sees angry people wanting the deaths of all mutants, an action that actually happens. He then sees mutants being led away into termination camps, with both human soldiers and Sentinels making sure the mutants don't try anything. But then he sees that the Sentinels also turn on the humans, so the robots can take over the entire world for themselves.
Charles ends the link and says that they've failed -in the future his dream of mutants and humans living together in peace never happened and instead, everyone has suffered. Cyclops can't believe the Professor believes Bishop's story and even Wolverine agrees with him -Bishop was trying to kill them all a few minutes a go. Bishop says that it was one of the X-Men who did the assassination and started off the whole dark future, but then his transceiver starts to flash. He tells them that something else has come through the time portal. Wolverine really thinks he's crazy to be going on about a time portal, but Xavier tells the X-Men to go and take a look. Bishop leads them back to where he appeared. A quick scan reveals that there is a high energy reading here.
Nimrod has also used the time portal! As it begins blasting everyone it can, Bishop explains that Nimrod is an advanced Sentinel unit. Wolverine doesn't think much of it as it's so much smaller than the ones he's been used to facing but he soon learns the hard way on the powers it has. When the X-Men's powers don't seem to be doing any damage, Storm uses the elements to try and take the robot down.
Storm freezes Nimrod and then she, Bishop and Cyclops blast it to pieces. Cyclops think they've done it but Bishop points out that Nimrod is very tough to kill -as it starts to pull itself back together again!
Bishop quickly runs up and sees that Nimrod also had a transceiver on him -so he blasts it, sending the parts of the robot back through to the future. The X-Men now believe that Bishop really is telling the truth and head back home. Wolverine wants to know which one of the X-Men is the assassin, but Bishop says he can't remember. Just then, Rogue enters the room and says everyone looks stressed out. Gambit then enters saying everyone can relax now, because he's returned. But the moment Bishop sees him things get ugly.
"You! You're the reason I've come back! Traitor! Your future ends NOW!"
NOTES
The two mutants first seen with Wolverine in 2055 aren't named and don't appear to be based on anyone in the comics.
Whilst visiting Beast, Rogue brings him a copy of You Can't Go Home Again.
The box art for Assassin features a certain other Marvel character...