"Chief, I need you" Cortana's sweet voice brought the Master Chief out of his long sleep as the cryo-chamber began its warm up sequence. The Chief was suddenly aware of being back in the rear section of the Forward Unto Dawn inside one of her cryo storage bays.

"What is it Cortana?" The Chief asked pulling the release handle popping open the cryo-pod's hatch.

"My sensors are limited but we're detecting English communications from a portal"

"A portal?" The Chief queried grabbing his trusted MA5B Assault Rifle flicking out the cartridge checking it was full before replacing it.

"It just appeared there appear to be unknown alien life-forms heading for the portal" the AI reported.

"And you think there are humans on the other end?" The Chief asked suddenly hoping to return home after being marooned in space following the firing of the Halo ring over the Ark.

"Probably I don't recognise any of the frequencies they appear antiquated." She said "Chief! We got incoming some of those aliens are breaking off and heading for the Forward Unto Dawn."

"Are there any Longswords or Pelicans left?"

"One Pelican in bay two" She said after a moment "sending warm up command" she said knowing what he'd want next they'd been together long enough. "Yank me" she said the Chief did not hesitate instead he just pulled the chip containing Cortana's essence from the podium and inserted it into the back of his helmet. Instantly the Chief felt the strange cool sensation he felt when Cortana entered his MJOLNIR armour suit with Cortana secure the Chief headed through the wrecked Forward Unto Dawn.

Above the streets of New York a strange portal had been opened by the Asgardian Prince Loki and was disgorging hundreds of alien Soldiers into Earth's atmosphere. On the war-torn streets below the SHIELD response team known as "The Avengers" stood ready for the next group of enemies.

"I have unfinished business with Loki" the Asgardian Prince Thor said, Loki was Thor's adopted brother they had grown up together but while Thor was due to rule Asgard Loki had felt he'd been forgotten.

"Yeah, get in line" Clint "Hawkeye" Barton said inspecting one of his arrows.

"Save it" Captain Steve Rodgers said dressed in the stars and stripes uniform of Captain America carrying the circular shield. "Loki's going to keep this fight focused on us and that's what we need. Without that these things would run wild" he said walking through the Avengers. "We got Stark up top he's going to…" He started before being interrupted as a motorcycle carrying Dr Bruce Banner pulled up behind them.

"So this all seems horrible" he said getting off the motorcycle.

"I've seen worse" the red haired Natasha Romanov said looking at Banner sceptically

"Sorry" Banner said looking at Natasha not long before Natasha had seen his angry side up close and it hadn't gone well.

"No, we could use a little worse" she said

"Stark, we got him…" Rogers said

"Banner?" Tony Stark asked flying above in his Iron Man suit

"Just like you said" Rodgers confirmed

"Well tell him to suit up, I'm bringing the party to you" further down the street Stark's Iron Man could be seen turning around a building coming towards them. Behind him a massive flying alien followed smashing through a building as it came.

"I don't see how that's a party" Romanov said looking at the flying beast as it dropped to the ground smashing everything out of the way as it closed. Iron Man flew over the gathered Avengers as the beast continued to close on them. Banner turned towards the beast.

"Dr Banner now might be a good time for you to get angry" Rodgers said stepping closer to him.

"That's my secret Captain" Banner said "I'm always angry" his body beginning to transform into the giant green skinned Hulk destroying his clothes as he transformed. With a single punch the Hulk smashed the nose of the flying beast turning it over on itself shattering its armour.

"Hold on!" Stark called out as Iron Man reappeared blasting the beast with a missile shattering it into several pieces.

Entering the atmosphere inside the Pelican the Master Chief was immediately engaged by the hostile aliens. Quickly the Chief realized that there was a massive inhabited city below and that the aliens were attacking that too. "This is Sierra 117 to any UNSC forces please respond." He called out blasting several aliens with the Pelican's forward cannon turret.

"This is Captain Steve Rodgers, I don't know what the UNSC is but if you're human and can fight lock on our position" Captain America responded from the ground the Chief was worried that this Captain didn't know what the UNSC was but followed the command diving the Pelican down over the streets of New York.

"Something doesn't look right, this isn't the New York we know Chief" Cortana said the Master Chief agreed everything looked primitive but he couldn't think about that for now. Flying over the streets the Chief flicked one of the cockpit buttons releasing several weapons pods.

The large green dropship swooped over the Avengers weapons pods slamming into the ground beside them before it landed several feet away. The rear door quickly opened and a single green armoured individual stepped out Rodgers thought individual because he was huge over seven feet tall the Hulk was bigger but only just. Over the green armour Rodgers saw he carried a large assault rifle and had another weapon over his back.

"I am Master Chief Sierra 117" he said as if that should mean something to them all.

"Welcome to New York" Rodgers said accepting him as a fellow Solider even if his origins were unknown. Above them more alien behemoths were entering the atmosphere.

"Call it Captain" Stark said essentially surrendering control to Rodgers the Master Chief decided introductions could wait.

"Alright listen up, until we can close that portal our priority is containment" he said looking up at the portal "Barton I want you on that roof watching everything calling out patterns and strengths, Stark you've got the perimeter if it gets more than three blocks turn it back or turn it to ash."

"Want to give me a lift?" Barton asked Stark

"Right, better clench up Legolas" Stark said stomping over grabbing the man by the back of his clothing pulling him up into the air.

"Thor you've got to try and bottleneck that portal slow them down you've got the lightning light them up." Rodgers said Thor nodded spinning up his hammer throwing it and himself into the air. "You, me and the Chief we've got them on the ground" he said looking at Romanov and the Master Chief the Chief did not reply instead he just raised his assault rifle sighting the aliens in the skyscrapers around them. "Hulk" Rodgers said to the transformed Banner "Smash" he said giving the simple instruction the massive green creature threw himself into the air engaging the aliens hanging off the building above.

The battle quickly turned into a free for all with Iron Man, Thor and Hulk keeping the enemies contained while Barton continued to shoot down enemies and call out numbers from his rooftop the Chief, Romanov and Captain America fought on the ground. As he gunned down yet another enemy Solider the Chief paused for a moment to take note of his new team's capabilities. Both were very capable of fighting hand-to-hand as good as any Spartan he had fought with the Captain's shield seemed to ignore every law of physics as it bounced off of enemies all around them. Romanov was something else a crack shot with her pistols she wasn't afraid to try the Chief's weapons either grabbing an M7 Submachine Gun, that had fallen out of one of the Pelican weapon pods, to gun down enemies the Chief was pretty sure that despite her small frame she could manage to wield two of them if she wanted.

Turning on the spot the Chief gunned down another alien only to be confronted by another just as the last bullet left his assault rifle. Discarding the weapon his hand dropped to his side pulling up a Sangheili energy sword cutting down one enemy he spun cutting down another and then a third. Glancing around he noticed the aliens suddenly didn't want to close on him. Catching a glance from both Rodgers and Romanov he saw that both appreciated his new found surprise. Several long range shots of the alien's weapon slamming into the MJOLNIR's shields draining them significantly but the Chief turned quickly as if he'd barely been touched dropping the sword back onto the thigh magnetic strip of the armour. From the armour's back he drew a BR55 Battle Rifle sighting the enemies he was against quickly sending a burst of fire into the heads of all three.

"Full of surprises aren't you" Romanov said approvingly moving next to him beside a yellow taxi.

"It helps for so many situations" the Chief replied taking a shot at several more enemies unfortunately after taking out one another three seemed to turn up the Chief couldn't help but think they were like Unggoy harmless alone but in groups trouble.

"Captain none of this is going to mean a damn thing if we can't close that portal" Romanov said seemingly reading his mind.

"Our biggest guns can't touch it" Rodgers said

"I've been analysing the beam controlling the portal Chief I haven't found a way in yet" Cortana said to the Chief pretty much confirming what Captain Rodgers had said.

"Maybe it's not about guns" Romanov suggested

"You're still going to need a lift up there." Rodgers said

"I've got a lift, need a boost though" she said Rodgers turned his shield upwards and after a couple of strides Romanov jumped up onto it jumping onto one of the alien's skiffs.

"Now there's just us" Rodgers said looking at the Chief who replied by shooting down three enemies. "Right" Rodgers confirmed. As they fought Iron Man, Hulk and Thor all passed through the combat zone cutting down enemies but it was mostly the Chief and Captain America.

"Captain I need a boost!" The Chief called out snapping up a rocket launcher from one of the weapon pods striding towards Rodgers the Captain positioned his shield upwards and the Chief jumped up onto it surprisingly the Captain and his shield stood up under the weight of the Chief in his MJOLNIR suit gaining the extra height the Chief fired two shots from the launcher down into groups of enemies blowing them to pieces and yet more came.

"I can close it, can anyone copy, I can close it" Romanov said her voice sounding struggled.

"Do it" Rodgers ordered

"Negative, I've got a nuke coming in" Stark said flying above "and I know just where to put it." He said confidently the Chief did not appreciate having a nuke shot at him and noted it as something to look into after this fight. Stark controlled the missile's path sending it, and him, up into the portal the Chief had entered through.

"Com'on Stark" Rodgers said looking into the sky as there was no sign of Iron Man's return through the portal. "Romanov, close it" he ordered just as the Iron Man suit fell through the closing portal. "Son of a gun" he said all around them aliens were falling no longer controlled by whoever was beyond the portal.

"He's not slowing down" Thor said spinning his hammer ready to try and catch the falling Stark. Above them however the Hulk was already in motion leaping from building to building catching Stark in mid air and bringing him back to the ground.

The Iron Man laid on his back looking down at him the Chief remembered seeing many downed Spartans in the same position. Thor moved quickly pulling the gold faceplate from the red armour but the rigidness of the armour hid any breathing movement from Tony Stark. The Hulk screamed loudly and suddenly Stark was awake once more.

"What the hell just happened?" Stark asked looking around "Oh please say no-one kissed me" Stark said still laying on his back.

"We won" Rodgers said sitting down on the ruined road.

"Yay" Stark said sarcastically "let's just not come in tomorrow?" He asked not moving yet.

"We're not done yet" Thor said Tony audibly groaned at the thought of movement but their job was really done. The Avengers team including the Master Chief went up into Stark Tower and confronted Loki from there Thor whisked the rogue Asgardian away to a prison cell on Asgard. The other Avengers went their separate ways while the Master Chief and Cortana were debriefed by SHIELD. The organisation's director Nick Fury acknowledged that the Master Chief's armour, the Pelican and weapons all belonged to the warrior while Cortana was her own separate entity and each would be treated as such. Because of the Chief's actions during the Battle of New York SHIELD agreed to make work with him trying to get back to his own time while offering him security work through SHIELD protecting Earth's people from threats.