The scene opens up with an exterior shot of a gated mansion. In the woods surrounding this estate, Gambit can be seen sprinting towards the residence, extending his staff while doing so. He plants it into the ground and with that running start, he is able to catapult himself over the gate. He pauses briefy to check out his surrounding and continues running towards the house. Gambit approaches a glass door that leads to a hallway filled with antiques. He smirks, drawing a smiley face on the door with his finger. The image crackles with blue energy and the door dissolves. He pulls out an aerosol can and sprays it towards to floor to allow him to see the extensive security laser grid near the floor. From his various pockets out of his coat pockets and from his utility belt, Gambit puts together another staff with a numerous amount of parts, one of which have a lever. He jumps to a nearby cabinet, crouches down and presses the lever, allowing the pointed ends to embed themselves into the wall, connected by cable wires that are attached to the body of the staff.

In a bedroom within the house, Warren Worthington’s wings twitch in his sleep. Back in the hallway, Gambit zips up his coat and props himself on the main body of the staff. He presses a button and it allows him to slide long the cable wires. When he reaches the end of the line, Gambit lowers his body and draws the shape of a circle on the floor. The energy crackles just like before and creates a calm explosion. He jumps through the hole and lands in front of a green artifact, seemingly one half of a ceramic spider. When he picks it up, the doors to the room swing open, with Warren asking if there is anything he wants in the room. Gambit responds by throwing a card at the winged mutant and it explodes the moment it makes contact with the floor.

From outside, a wall explodes and Gambit runs through this freshly-made hole and jumps over the gate. He walks slowly to a hooded man, handing him the artifact. As the mysterious man examines it, he hears the sound of wing flapping and turns his attention to Warren, who charges at him. The man, who is really Mesmero, places his middle and index fingers on his temple, shooting him down with a mental blast. Suddenly, a magnetic hum can be heard as the nearby gate begins to warp unnaturally. Mesmero notices this and tries to run off. However, the metal posts are quickly pulled out and stab into the street containing Mesmero. Magneto finally descends from the sky, telling Mesmero how impressed he was at hypnotizing Gambit to do his stealing. Mesmero attempts to use a mental blast on Magneto but he advises the hooded mutant not to bother as it won’t affect him. Mesmero turns his head, mentally suggesting Gambit to throw a charged card at Magneto. As Gambit does this, the metal prison tightens around the psychic mutant. Magneto demands him to “release his mental hold” immediately and Mesmero agrees. Gambit shakes his head, wondering how he got to this location in the first place. Magneto loosening up the cage a little bit and steals the artifact from Mesmero. Magneto flies off, magnetically taking Mesmero in his cage and with Gambit trailing behind on the street. Warren regains consciousness and looks ahead, saying the name “Magneto”.

The scene shifts to the next day, with a dove flying into the Xavier Institute’s airspace. The X-Men and the New Mutants are playing a game of softball with Jean as the pitcher, Beast as the umpire, Scott as the catcher and Bobby, who is currently up to bat. Jean blows a bubble from her gum as she prepares to pitch the ball. Bobby doubts that Jean will be able to strike him out and Scott gives Jean some pitching signals. Jean grins and takes off her glove, allowing the softball to float in a circular pattern near her. Bobby complains to Beast that Jean is using her powers but Beast just tells them to continue the game already. Scott encourages Jean, telling her that he’s not going to hit the ball. Jean takes the ball back into her hand and pitches it. Bobby encases the bat in ice, giving it a wider diameter and he hits it. His teammates cheer him on as he runs to first base. Kitty runs to third base and phases through Jamie, who is trying to catch the ball. He is disoriented from the phasing and drops to the ground, producing three clones. Jamie catches the ball and the clones dissolve. Beast sighs as Bobby yells out, “Mutant ball!” Amara pitches the ball to Jean, who telekinetically stops the ball. She hits it and Sam heads to third base, using his power to catapult his way over there. Knowing about Sam’s lack of control over his mutant ability, Kurt teleports from his third baseman position. Amara pitches another ball for Ray but the ball heats up and catches on fire, barely missing Ray and Scott, who look at the hole in the wooden bat and the chain linked fence. Later, Jean pitches the ball to Roberto, who goes into Sunspot mode to hit the ball. As he makes his way to first base, Scott raises his sunglasses and blasts the baseline into a steep trail, forcing Roberto to fall down into it as he slips out of Sunspot mode. Roberto’s ball is still in the air and Kurt teleports into the air to retrieve it. He teleports to home plate to get Kitty out. Kitty phases into the ground and touches home plate. Suddenly, a shadow looms over Kitty, Kurt and Scott. All of the students look into the bright sky to see Angel descend to the pitcher’s mound. Scott asks him why he is here and Angel responds that he needs to see the Professor promptly.

At Magneto’s base, iron doors slide open with Magneto entering the room. He asks Mastermind if he has retrieved any information regarding the artifact. Mastermind confirms this, stating that the spider stone is merely one half to an ancient key and that the second half of it resides in the Tisdale Museum in London. Magneto wonders what the key is meant to unlock but Mastermind isn’t certain as Mesmero’s psychic abilities are formidable. Magneto then spins the chair around, startling Mesmero a bit. Mastermind places his hands on Mesmero’s cheeks to scan his mind. Through these memories, he sees Mesmero using the first key to unlock the first door. Mastermind releases his hold on Mesmero, gasping in fear. He responds to Magneto’s request for the information, stating that “The relic will help unleash the most powerful mutant the world has ever seen. En Sabah Nur. [He] will know him as Apocalypse.”

At the mansion, an image of Mesmero’s face can be seen on a computer screen. Professor Xavier asks Angel if this was the same mutant he saw the previous night, which he confirms. Amara and Kitty are looking through the door crack when Bobby teases them about checking out Angel. The two girls run over and Bobby remains, becoming intrigued by the conversation. Professor explains to Angel that they have encountered Mesmero once before as he had manipulated Jean into stealing for him. Beast informs them that the rings formed a key of sorts and that the second half of the Spider Stone is in London. Xavier becomes concerned about the stone unlocking the second door and feels that they must retrieve before Magneto can get his hands on it. Bobby leaves from his crouching position, ready to go on the mission. Beast and Jean tell him that he can’t come along, partly because his aversion to following rules. Bobby begs them to go on the mission as they walk off.

Magneto and Mastermind enter the chamber, seeing that Mesmero has vanished and has taken the Spider Stone half with him. Mastermind becomes worried about the joining of the two halves but Magneto insists that this will not happen.

At the mansion, Kurt teleports into the infirmary, offering Rogue’s dinner which consists of spicy enchiladas and black beans. Rogue is upset at Kurt for surprising her and is not in the mood to eat her dinner. Rogue asks where Logan is and he tells her that Wolverine and Storm are tracking down Mystique. He adds that since Scott and Jean are on a mission, he and Kitty are in charge of the basic operations at the manor, including Rogue’s well being. Kurt to spoon feed Rogue the enchilada though Rogue just wants him to go away. He asks if she should be treating her younger brother this way and Rogue retorts that they are not related as Mystique gave birth to him but she was merely adopted. Kurt does not want to hear this, insisting that they are in this situation together and that he will always be there for him. He teleports out to the Kitty to ask Kitty to make her an anchovy jalepeño pizza. Rogue sighs and puts her hair behind her left ear, grinning.

In London, the X-Men’s helicopter lands on the top of a nearby parking garage. Beast deduces that the Acolytes are probably not at the museum yet as it seemed to be in order. Not wanting to take any chances, Xavier wants to quickly get there. He turns his head, telling Scott to inform a particular stowaway that they have arrived. Scott gets confused. Bobby is sitting in a cabinet, eating a bag of potato chips. Scott opens it and offers a hand to pull him out.

At the Tilsdale Museum, the entrance doors violently open up as Magneto and his Acolytes enter the facility. He commands his followers to separate and protect the building. In a break room, a security guard’s solitaire game is interrupts by the alarm system. He speaks into his walkie talkie and tells someone to look at the alarm system for glitch, refusing to do so himself during his break. As he is about to put down the Five of Hearts, a glowing Ace of Clubs gently lands on the table. The guard looks up and sees Gambit. He looks down to the card and the force of the explosion knocks him into an adjacent cabinet. He stands up but Gambit forces him into the cabinet. Gambit looks the table briefly and places the Five of Hearts on the Six of Spades.

Another guard walks down a corridor consisting of a variety of armor. He walks past Colossus and as he just passes the Russian mutant, he realizes that something is wrong and turns his head. Colossus looks down on him and grabs him by the shirt. In another corridor, another guard is running in trepidation as a fiery horseman and his equally fiery horse chase after him. Pyro turns the corner, laughing maniacally. The horseman and his horse block the guard’s pathway and merge into the shape of a skull. The scared guard runs into the storage room to protect himself. Pyro melts the doorknob after he closes the door.

Outside of the museum, Iceman’s boots begin to frost over as does the rest of his body. Cyclops notes that Magneto has already let himself in as the entrance doors had been unnaturally forced open. Beast tells Iceman to stay with him and Iceman concurs, adding that he’s got his back. Beast replies that, “[he] doesn’t have a clue”.

In the museum, Magneto leaves an elevator, spotting Mesmero turning a corner at the end of the hallway. Magneto slightly raises his fingers, commanding the elevator to skid out of the structure. In the museum lobby, Sabretooth walks past a series of window and sees a shadowed figure floating by. The figure, who turns out to be Jean, opens up the windows and telekinetically wraps a window drape around Sabretooth. As he floats away, Angel flies into the museum and he ascends to the sky window, where a blast of ice forms into a pole with Iceman and Beast sliding down it. Sabretooth is breaks out of his fabric prison and falls to the floor. He turns around and charges and Cyclops at a moment’s notice. Cyclops, however, fires an optic blast at Sabretooth, sending him into Colossus’s torso. The two teams reform and Gambit seems prepared to fight them.

Mesmero wanders down a hallway, immediately approached by Magneto. Magneto steps aside and sends the elevator chasing Mesmero. Back in the lobby. Angel dodges Gambit’s card projectiles and flaps his wings to deflect the final two cards. These cards head back to Gambit and knock over a nearby retaining pillar. Colossus catches the pillar and chucks it at Cyclops, who slowly blasts it into smaller pieces. Beast starts jumping around the lobby to baffle the Acolytes, dodging flames and cards. When Sabretooth is about to hit Beast with a booth of random paraphernalia, Iceman forms an ice shield to protect him. Jean arrives to help them, levitating Beast into the air. Once that’s done, Beast jumps onto Sabretooth. Angel charges at Gambit, who is fighting the winged mutant off with his staff. As Angel flies past Gambit, a stream of fire fies towards him, assuming the shape of Angel. Pyro commands the fiery Angel to attack Angel. This attracts Iceman’s attention, causing him to jump off the balcony forming an ice slide and he freezes Pyro’s hands to prevent him from shooting out more flames. The fiery Angel dissipates and Iceman makes a gesture that implies that he’s got Angel’s back.

Mesmero runs into another room, heavy breathing from escaping the moving elevator. He looks around, eventually eyeing the second half of the Spider Stone. The elevator crashes into the room and one of the cable wires wrap around Mesmero’s leg. The first half of the Spider Stone slips out of his hand as this happens. The wires pulls Mesmero into the loosened elevator and Magneto begins to compress the elevator’s volume. Magneto tries to grab onto the first Spider Stone half but it begins to levitate on its on, flying around the room. The second Spider Stone half breaks out of its glass case and mimics the flight pattern of it’s complementary piece before merging. As it approaches Magneto, it glows in a blinding green light. It produces a force, sending Magneto into a wall and transforms into a green, transparent spider. The spider walks away, briefing stopped by Magneto’s powers. After resisting the pull, the spider starts to drag Magneto as he still is trying to stop it. Mesmero breaks out of his prison and chuckles. The spider burns a hole into a wall and with Magneto’s power influence, two support beams from the wall fire back at Magneto. The spider lands on a few cars and crawls away. Professor Xavier sees this from just outside the museum, looking up at Magneto. Moments later, Magneto tells him followers to destroy the spider, regards of the consequences. Professor X doesn’t like this idea, stating that they don’t know anything about the spider. Magneto refuses to listen to him, flying after it. The X-Men runs to Xavier and are told not to destroy the spider as it has answers they may need.

Colossus runs down a street, arriving at a warehouse. He simply runs through the brick walls and as the they leave the warehouse from the other side, Colossus jumps on the spider’s head and tries to wrestle with it. The spider grabs him and electrocute the metallic mutant. He tosses Colossus onto the debris and Sabretooth jumps down with a large piece of wood. After taking a few swings, Sabretooth is tossed into a minivan. Pyro shoots out some flames at the spider, circling it with flames. As Pyro retrieves the flames, the ground begins to rumble and he finds out that the spider is digginer underneath the street and heading towards the docks. Gambit looks at this from atop a building and jumps down.

Just outside Tilsdale Museum, Mesmero begins to run off but is stopped by Professor Xavier who enters his mind. Within the mind, Xavier sees Mesmero unlocking the first door and a pair of yellow eyes opening in a black background. Realizing that Mesmero had left, Xavier mutters “Apocalypse”. The spider dives into the river and Angel spots it’s green glow in the water. Cyclops and Jean arrive to see this. Jean levitates herself and forces the spider to rise from the water, contained in a telekinetic force bubble. The spider breaks out of the shield but expanding it, causing it to hit Jean. Cyclops runs up and catches her. He looks at the spider and starts blasting at it, having no good shot. Beast commands Iceman to create an ice bridge over the river and he does so, carrying himself, Beast, Cyclops and Jean Grey with him as Angel flies across.

On the other side of the river, the spider causes chaos in the streets. Gambit, who had hijacked a double decker bus, blocks the spider’s path and swerves and jumps on the side of the bus as it slides on its other side towards the spider. The bus lands on the spider’s body and Gambit charges up the entire bus. Angel arrives but flying further into the air as the bus explodes. Seeing that Gambit had slowed down the spider, Magneto descends from the air and walks towards the fiery remains of the explosion. The spider rises as the X-Men’s helicopter lands and Iceman’s bridge comes to an end. Xavier yells out to Magneto, telling him not to destroy the spider. Magneto refuses, still insisting that he should kill it. He uses his powers to contain the spider and succeeds, leaving behind a smoky Spider Stone arifact. Xavier wheels over and explains to Magneto that he fell for Mesmero’s trick. It seems that Magneto was the only one capable of defeating the spider. However, the spider was actually a guardian prepared to defend them from Apocalypse and with its destruction, the second door is now opened. Angel notes that Mesmero took off, going southeast. The X-Men ponder about what will happen next.

In Tibet, the second door slides open.