The covenant forces made their attack stronger as all covenant fleet started to embark on the surface, preparing to use everything on destroying the UAC and also targeting the city as well. Half the population has abandoned the city and fled into the north away from the battle while some decided to take refuge inside the bunkers, they were made there just to avoid heavy casualties if the covenant ever arrived and glassed the city, that way they can try to get the people out of the bunkers if they can breach through the rubble of the glassing.

Right now the covenant has started retreating back after the covenant battlecruiser got new orders and started withdrawing for now, turning towards the city while the main ship will target the main base directly, the other ships will surround the area and prepare to deploy troops once they destroy the base. They will be going all out on this so they are not stopping until they get what they want, if they destroy the base then they will just have to dig their way down to the underground facility to get what that Promethean wanted.

While the covenant withdraws and some of the infantry are still fighting against the UAC, the Master Chief was still fighting through some grunts until he made it inside the lich by using its gravity lift to reach inside. Just when he made it inside he quickly threw a plasma grenade to any covenant he saw, hitting a grunt to the chest and sending it running to the side near an elite before he ends up blowing up and taking out that elite too, Chief will look around seeing it's secure then he started moving to the control room.

Elsewhere the Spartans have abandoned the grizzly tank after they eliminated the last covenant forces and noticing that large ship getting closer towards them, seeing they are preparing something big and so Hunter quickly helps the marines get back inside. They will have to get inside the compound and head further down to reach the elevator, Rookie will stay behind watching the door and waiting for the Master Chief to arrive while both Pinky and Hunter joins the others, noticing right now that Rookie isn't with the crowd so Hunter will return to the surface while Pinky gets on board the first elevator down to the facility.

Rookie stood by the side of the opened door looking out seeing that lich was moving away. Hunter comes over and taps on his shoulder, quickly turning his body towards her. "What are you doing?" Hunter asks "We have to go now!"

Rookie looks back and notices Chief jumping out of the lich then looks back at it seeing it's about to go crashing hard on the ground, he will look up above it seeing the large cruiser coming down upon this field. "I don't think that ship is going to give us more fighting." Cortana said to Chief "We have to get inside."

Chief will look out to the city seeing two battlecruisers bombarding the city and preparing to glass it. "I can't abandon them…"

"Chief we can't do anything about them right now… It's too late."

Chief looks back up seeing that ship getting closer and it's charging its planetary plasma cannon. "We have to go… NOW!"

Chief makes a run for it back to the facility while that ship started to channel its power ready to destroy this whole area. He runs at full speed towards the base seeing both Rookie and Hunter standing there, Hunter was waving her hand to hurry while Rookie looks up at that ship then started moving back inside with Hunter inside the room before Chief can run right in. The three Spartans makes a run inside the base and quickly moves all the way down to get to the elevator, seeing the last group on the elevator and is waiting for the three to get on board and just when they finally made it they quickly started going down further underground but halfway to their destination that cruiser finally fired, firing that beam down to the surface and completely annihilates the whole area, sending the flames and debris consuming the whole inside of the base and they started coming down to the elevator, heading right towards them and almost consumes them however they made it to the bottom and they quickly just jumped off of the elevator to avoid critical burns however only three got killed by the flames and didn't have time to escape, once everyone jumped out of there, one scientists quickly presses a button on a display console causing the elevator doors to close to avoid the rest of the flames and the rest of the debris that comes collapsing over the elevator shaft, closing them underground.

"About damn time you guys made it down here." Pinky was standing nearby looking at them getting back up off the ground. "I guess this is all that was left?"

Hunter looks over to Pinky "Yeah…" She looks to Chief "But we got ourselves a Master Chief…"

"And now were all trapped down here." Cortana said to them "For now.'

"We have enough rations down here to stay for two years."

"The covenant isn't going to wait for us to starve." Hunter said walking up to Pinky then to Rookie "They will be coming down here with force."

"So where are we?" Chief asks taking a few steps forward checking the area, seeing they are in this large wide area the size of a warehouse, it shows a few warthogs and scorpion tanks against the side of the walls. "What is this place?"

"This is the UAC headquarters." Hunter said

"I thought the UAC headquarters were on the surface."

"That's what everyone thinks." She walks closer to him "Down here is where all the work begins."

"So why are Spartans protecting a corporation?"

"You got to take that up with Samuel Hayden." Pinky said "He will tell you everything you need to know."

"And where is he?"

"Rookie will escort you to him." Hunter looks to Rookie "Go on, we will take care of the situation.

Rookie will not and looks to Chief he nudges his head to the side then started walking off heading to the room that is on the other side, Chief will decide to follow him as he doesn't really have a choice. While they go off to meet Doctor Hayden, all of the UAC marines are all preparing themselves for battle against the covenant and escorting scientists and doctors in some places although It's unknown on how the covenant are going to come down here due to the headquarters is stationed right underneath the mountain.

Back on the surface inside the covenant flagship, they are preparing to deploy troops and will be using heavy ordinance to reach the headquarters but it will be a while before they can dig all the way to the place. Inside the flagship this promethean was standing in the hanger room seeing this large force of covenant standing in formations preparing to board inside the phantoms that was ready to send them to the surface, he will just watch and smile as the covenant will soon swarm over the surface.

The promethean will stop smiling when he felt Jul 'Mdama behind him. "Is there something on your mind?"

"No." He stands next to him "However there are those who judges you on this task, care to explain what this gate can do once we reach it?"

"There is an item which can open the gate, I cannot open this gate because… I do not have the power require to do it but I know the humans have it."

"What is it and I shall retrieve it from these humans."

"From what I believe… The humans call it an 'Argent Accumulator' and with this power source I can use it to open the gate. With the gate open I can unleash a great power across the galaxy." He looks to Jul 'Mdama "With it you can finally get what you wanted, the human's extinction and my goal to finally return to where I belong."

"We will storm this base and kill every human down there, with this weapon I can restore the covenant and together we can finally take back everything."

"Yes…" He looks forward "Everything…"

Back in the UAC headquarters, both Rookie and Chief will end up going inside the office of Doctor Hayden where he will be standing in this large room looking at this screen behind his office table, it was a window showing the outside of this beautiful view, it's almost as if this room was on the surface looking at the beautiful view however it's likely fake and made just to make things nice around here.

Both Rookie and Chief walks over to him noticing a few stuff inside, some look ancient looking and Chief got his attention to this brown looking stone statue. This was a marine that shows no name and shows a similar appearance of the Master Chief however he appears as more muscular than him and this statue is the same size as him, it's like seeing himself but huge. Rookie would be looking to this wide stone tablet against the wall, protected by glass and shows the top part of it is removed but the rest pretty much still explains because it only shows a picture of this marine standing in the center wielding a large blade, having it in the air after slicing this demon in half while the others try crawling their way up to grab him but only one of them is grabbing his left arm. It also shows two other people in there wearing armour covering their body, they appear to be humans wielding swords striking through the demons attacking the side and they appear to be protecting the marine with the large blade because on his left hand shows this white cube that is glowing.

"Welcome back to the world of the living Master Chief." Hayden said turning back and looking towards him, getting the two to turn to face him. "My name is Doctor Samuel Hayden."

"You know who I am." Chief takes a few steps forward looking at him.

"This guy is not what I thought he would be." Cortana said looking at his robotic body.

"Yes well…" He looks down at his body then to them "That is a long story and you don't have time to listen to my story."

"What is all of this." Chief looks to that stone marine then back to Hayden

"Knowledge… Knowledge that we have found on this planet." He walks closer to his table placing both hands on it to lean on it, looking down at the screen attached onto this office table. "We have found an ancient race that is far different than the Forerunners, yet the covenant still wants to destroy all of our work."

"Care to explain all of this?"

"Well then… Since we got a lot of time and it will be a while before the covenant can enter the facility." He leans back "VEGA."

"Hello Master Chief." He said out loud in the room for them all to hear "My name is VEGA, an artificial intelligence here to serve Doctor Samuel Hayden and the UAC facility, I control the whole network and I can help you explain all of this."

"What is the UAC?"

"Union Aerospace Corporation, one of the best and strongest corporations in the galaxy, it is populated with twenty-five thousand six hundred and seventy-five personnel, focusing on research of our ancient prehistoric human civilisation that died out billions of years ago, same time of the Forerunners."

"We discovered that the Forerunners were once at war against the parasites which you already knew that, but what you didn't know is that we believe this race was part of that war, or against them. This planet once belonged to that civilisation and we believe there have been other planets controlled by this race, all we found was relics and a time that shows us only a few but we are slowly digging more of their relics and discovering the truth about our past humans, we believe we may found a co-ordinance of a planet connected to this one. This is the second ancient race we have discovered in the galaxy, however we discovered that we found this civilisation on mars before It all got destroyed."

"What do you mean?" Chief asks

"VEGA."

"In Twenty-one-forty-two planet mars was colonised and became a large city, the first UAC was established and prepared to research on the ancient race however a sudden accident happened. Everyone died and everything that happened there has been classified for a hundred years, the UAC in that time discovered an ancient civilisation however before they had the chance to discover something great, everyone was killed and it was lost forever."

"Is the covenant after the same thing?"

"That is a possibility." Hayden said "The covenant will try everything on gathering ancient artefacts. They can go after Forerunner technology all they want but this research here belongs to us, with this knowledge and technology we obtain and also this power called Argent Energy, we can finally help the UNSC create the Spartan fives."

"So that's why Spartans are here." Chief looks to Rookie "To protect your assets."

"So you have discovered that there was another human civilisation long ago before you all were even born." Cortana said "Well that does sound interesting but what I don't understand is that how can the covenant know about all this? I thought they wanted to go after Forerunner technology, not ancient human."

"I guess we have to go ask them."

"Master Chief… We cannot allow the covenant to storm this facility." Hayden said "We have discovered a powerful gate that lies near the Lazarus Lab, and with this gate we can harness its power to create Argent Energy, with you here we can continue our work and finally destroy the covenant."

"Well fighting the covenant is our specialties." Cortana said

"Well you Spartans and your affinity of guns is useful." Hayden said "There are different type of powerful weapons in this facility called ID Techs, there are three powerful guns that you may like are a class six and I'm sure you would like to use against the covenant. VEGA, show the two the facility."

"Certainly." VEGA will remove the screen showing in front of them and replaces them with a larger holographic display, showing this whole large facility that shows a large length than the city. Some large areas in this place will show they have names inside of the rooms, showing the armoury, the research complex, the Lazarus Lab and etc.

"Right now you are in Samuel Hayden's office on the higher level, you would have to go down to the center of the facility in order to make your way to the armoury, one of the weapons doctor Hayden mention before is there, the other two high class weapons are elsewhere, one in the Argent facility and the other is in the Lazarus Lab."

"Master Chief, whatever happens do not let them reach the Lazarus Lab –" A sudden shake occurs due to an explosion going off somewhere in the facility.

"We have a few breaches in the upper level of the facility." VEGA said "One of them is in the main entrance to the elevator."

"I have called the UNSC for assistance in this matter when we lost the surface to the covenant…" Hayden turns back and faces the window "They will arrive in a few hours, so it's best that we make sure that we stall the covenant time."

"Then I need to get a new weapon."

"There's another breach nearby in one of the research complex, you should go there first." VEGA said "You would have to take the hallway and move through two rooms to reach it."

"Good luck Master Chief, let's see if you fight valiantly than this guy." He turns back looking towards the statue of the marine

"Let's go Spartan." Chief looks to him then the two started heading out of there, leaving the room and started getting back to work.

"Why do I feel like he hasn't told us everything about this place." Cortana said while they move out

"He only answered the questions we asked him, it's not a problem."

"You sure?"

"Right now we need to stop the covenant from destroying the facility and getting their hands on something bad."

"If you say so."

Chief will stop and looks to Rookie "You go to the armoury; I'll deal with the covenant. We may need one of those guns."

Rookie nods and heads off elsewhere while Chief looks forward and noticing some marines running past him heading to the same location, double timing as the battle against the covenant isn't over yet. The covenant will continue digging down to the top levels of the facility, once they breach the rooms they will have to fight their way down to reach their destination and that's the gate that lies near the Lazarus Lab, the gate has its own room which is a large one and is connected to that lab and the only way to unlock the gate is if they use an Argent Accumulator in order to power it up, there is only three Argent Accumulators here in the UAC and they have all been locked up tight by maximum security, protecting them by the elite guards in the Lazarus Lab and might be transferred further underground if they have time.

Everyone inside the facility needs to brace themselves because with nowhere left to go and nowhere to hide, the only thing they can do now is fight like hell.