They’re in the control deck viewing a hologram of what appears to be the original Halo, the hologram pans out to see literally hundreds of Halos located throughout the galaxy. Cortana tells you to not intrude, hoping to learn something from this. Based on the visuals and the communication she determines something grave. That the Halo, which you destroyed, was only one of many, and that the Covenant is planning on using these as weapons against other planets, including Earth (if it survives its current attack). They believe that their gods planted these weapons in the galaxy and it is their job to use them to rule it without question. The hologram is being projected from a disk, and Cortana tells you that the disk is the crucial information, and you need to retrieve it at all costs. You jump and grab the disk, and several Covenant Troops suddenly appear, engaging their weapons and preparing to fire. The control deck windshield is cracked and open but the drop below would kill you, you look down to the ground a kilometer below, with Banshees spiralling about the ship. Suddenly and without hesitation, you leap from the control deck plummeting towards the ground much to the Covenant's surprise. With a well-timed leap you drop atop a Banshee and remove the Elite, flinging him to the ground You reach under and pull out the Covenant Troop, and hurling him to the ground far below. Before the Banshee can crash, you take control and head off to safety.
Interlude
Upon returning to the human headquarters in Earth City, you and Cortana deliver the newly acquired information to the commanding officers. When they open it they discover that the vast majority of the Halos existing are not active, and have actually never been stepped on by the Covenant. However there are many that are active and very close completion. The source for these is believed to be another race prior to the Covenant and that they had designed them as a way of generating control in the galaxy and it eventually became the only hope against the Flood. It is decided that the only way to stop the Halos from all going active is to access one of them and find a weak point in their structure, perhaps something that connects all of them. You and Cortana, along with thousands of other Marines board the recon ship, the Refuge and head towards the nearest Halo.
Level 05
Home On The Range
Upon arriving on Halo the defenses are very high so the Marines take pods to the ground to come in without be noticed. You land in a large canyon area between massive, steep mountains and go forward with a variety of vehicles that detach from pods, including a Hornet, a new Marine vehicle that flies similar to the Banshee.
You and your band of Marines charge forward, coming into quick conflict with the Covenant Troops within the canyon walls. You break out into a large field area where there are a great deal of Covenant forces with their weapons and vehicles. You notice three massive plasma turrets which are creating an impasse to the cavern which leads to the base. They are spread out over the battlefield, and in order to proceed to the Covenant base it is imperative to take out these out. If you don’t have a vehicle it’s in your best interest to get one, and head to the nearest turret. Using grenades, missiles and other firepower at the rear-power-generator of each turret will take it out after a while. Once the three are down the Marines will give you the go ahead to leave, and Cortana will guide you to the Covenant base. As you approach the Covenant base alone you find that it is heavily fortified with huge walls. This fortress is located next to a vast body of water, and there is an abundance visible snow falling within the walls of the base. Cortana directs you to a side entrance with minimal guards and you make your way into the outer wall fortification carefully. In the dark recesses of the outer Covenant base you trail your way through the generator rooms and using several elevators make your way onto the top of the bases’ walled defense. Taking out enemies as you go you clear the top sections of the walls and avoid firing from various turret points below. When you reach the end of the wall on the far side of the base, you drop below and down into the wall's interior structure, and back to the ground level. There you and Cortana get communication from the Marines that reinforcements are on its way, and they request that you open the main entrance gate. Cortana leads you to a power generator switch for the gate within a structure in the main court yard, and after dispatching Covenant troops you can open the gates and allow the Marines to enter. You exit the structure and continue down through towards the interior of the Covenant base. The Covenant Troops barricade the rear entrance of the base with their forces and there are two more turrets, which pose a similar threat. Once the issue with them is resolved as before, you and the remaining Marine forces continue through the Covenant base, which is by in large forged of rocky structures similar to the original Halo’s bases. Throughout the rear sections of the base you meet more resistance but eventually find you way into the main interior structure of the base, via a ramp down into Halo.
Level 06
Burn Baby Burn
With the base you find that it’s extremely dark and cold, with snow and ice in large quantities throughout the facility. You and any remaining Marines begin your trek into the depths of Halo, meeting with resistance in small pockets. You travel through corridors and tunnels, across familiar bridges and large landings. You come to another circular clearing outside the complex within a very large canyon. Above is an assortment of Banshees swirling about, and fortunately a pair of Hornets and a Warthog lie nearby a fallen Pelican that had somehow made it into this portion of the base. You can take any of the crafts and make your way to the far side of the canyon section, but it usually is more prudent to take out the Banshees first, as you have to unlock the entrance gate to continue to the next side, which is guarded by three more turrets. Find a quick way into the unlocking room in a central bunker in the canyon or take out the Banshees and then the turrets, and locate the unlocking room. With the gate open, Cortana tells the remaining Marines to fortify the area, and that you will proceed alone from there. You enter the gate. As you enter, you see a dim light at the end of this long tunnel. Moving forward the light gets bigger and soon, as Cortana explains, this is the central core of Halo, essentially it’s power source. You move into a large cavern, brightly lit by large lakes and pools of lava and magma. The walls are rock and natural formations, with strange writing on the walls.
Cortana is curious and as you get deeper and deeper into the core she begins to decipher the writing. She advises you that the writing, strangely familiar, was made by another civilization, which had discovered space travel a long time ago. They created Halo originally as a system with which to make sure the systems and planets followed their rule, creating the mythos that they were gods. She says this is how the notion of religion came into being. The virus later named the Flood, wrought havoc on them and eventually, Cortana believes, caused them to become extinct. Which, she says, is where the Covenant stepped in, a pact made between several of the strongest worlds, set to channel the power of Halo. They stopped and held the Flood at bay, presenting a formidable threat to the rest of the galaxy and then went off, conquering to conquer in the footsteps of the creators of Halo, their gods.
After penetrating a large section of the core, you come in contact with new Covenant enemies, some which appear strictly robotic, and they begin to attack. They pose a unique threat as they can only be destroyed in the back of their necks, which Cortana points out immediately. You dispatch these enemies, and head deeper into the caverns. As you travel further into the core, taking out hordes of enemies as they appear, Cortana guides you to what she believes in the source, a place the Covenant refer to as The Sanctuary. The deeper you travel the more violent the lava reacts and the more erratic the cavern shakes, with rocks and debris falling from inside. The last trek is across a long bridge, which leads to another white light. Cortana advises you that the bridge appears to be a trap and will begin to fall as you attempt to cross it. She tells you to run, which you do, and you enter the lit doorway at the end of the bridge, if you pass without falling.