Your current objective is to locate the Map Room to find the location of the Control Room. You will be dropped off at the beach head along with two teams of Marines.
The Covenant believe that what they call "The Silent Cartographer," is somewhere under this island. The Cartographer is a map room that will lead us to Halo's control center. The island has multiple structures and installations. One of them contains the map room.
This level isn't as hard as Truth and Reconciliation, and is also much shorter. It's much more fun, too! Anyway, right from the start, you will thrown into a battle between the Covenant. Foehammer also says one of the coolest Halo quotes here: "Touchdown! Hit it Marines!". Hop out the Pelican and use your Pistol to kill the Covenant. If you are getting hit too hard, use the rocks for cover and let your shields recover while the Marines give you cover. You shouldn't have too much trouble on this level, even on the harder difficulties. This section is especally easy, as you outnumber the Covenant by a quite a bit. Be careful, however, as you start with less than half full ammo for your Assault Rifle and Pistol.
Once you finish off the Covenant in this location as well as the area behind the large structure, a Warthog will be dropped off. Two Marines will hop into the Passenger and Gunner seat to help you. You must now find the location to the map room. From this point on, you can pretty much do the entire level in any order you want and explore to your hearts content.
Okay. Let's move out. Let's go find the map room that will show us the location of Halo's control center.
So, once you're in the Warthog, follow the shoreline until you reach a large hill guarded by some Jackals. Run them over to quickly dispose of them. If your Gunner can't shoot the one on the rock, hop out and use your Pistol. On lower difficulties, you can simply leave him, as he usually wont be able to hit you with his Plasma Pistol if you tear by at high speed. On higher difficulties, if you see any, get a Plasma Rifle. This cannot be stressed enough, Plasma Rifles are extremely recommended and will save you time and ammo fighting any Covenant. Continue up the slope and kill the Covenant up here. Try to run them over, but be careful not to fall off the edge!
There, in the cliff wall; I'll bet the Silent Cartographer is somewhere inside that facility. (On heroic/legendary:) They're already inside! We need to get in there quick, before they discover the location of Halo's control center!
You should notice a dropship unloading some Covenant, take them out and continue. Further along the path, you should see a large structure. Drive up to it and start taking out the Covenant with your Warthog. A good way to do this is to drive towards them and then quickly spin around to kill them if they try jumping out of the way. It makes you look like a pro, too! If you are running out of health and having difficulty killing these guys, head down the slope and pick up an overshield by the shoreline. The Grunts here like to throw grenades at your Warthog, so make sure you don't hit anything and keep moving. Running over Covenant is an easy way to kill these guys.
After killing all the Covenant you are able to in the Warthog, hop out (on higher difficulties) and kill the Elites inside the structure. Go back out and get your Warthog. By some strange mirical of the Forerunners, your LRV is just small enough to fit inside. Take a right (the only way you can do) and head down to where a group of Grunts and Elites are. You should also see a Golden Elite standing inside the doorway of another passage.
Don't let them lock the doors!
As you take care of the elites and the grunts there, the golden elite will retreat and lock the doors. Kill off the Covenant scum here and return to The surface. Just drive off the cliff to get back to the shore. Hopefully you will land on your tires and keep your Marines alive. If you don't want to risk this, just drive down the slope.
Head along the beach until you a reach a large clearing a trees and a small path leading into forest. Cortana will tell you that it will be the interior of the island. By an overturned Warthog, you will find some unlucky Marines along with two Med-Kits and a lot of ammo. If you have noticed, there are a lot of Jackals and other Covenant by the trees, so give them a closer look at your wheels. If you start getting low on health, grab the Med-Kits and continue. On lower difficulties (and if you good with driving the Warthog) you can jump the small cliff-like thing and flatten a ton of Jackals before driving out to engage the rest of the Covenant.
Now, there is a way to get your Warthog through the trees, but it is very difficult and not very rewarding. First, you have to start hugging the left cliff wall. From here, position your Warthog so it is facing the gap between the trees and the cliff wall, but make sure you are in front of the rock here. Now, just punch on the gas and you might make it through. If you do in fact get it through, you are under the risk of having it flip over and kill your Marines. So if you make it through all these obstacles, you can use the Warthog to kill the enemies ahead. Doing this trick requires a lot of patience, luck, and skill will controlling a Warthog. If you get your Warthog stuck in between the cliff and the tree, just back up and try again. You can also use your Warthog to get rid of the Hunters later on.
If you don't get your Warthog through the gap, just hop out and continue on foot. Kill the pesky Jackals in this location as well as the Elites and Grunts. Past this area is a place crawling with Covenant. Take them out, keeping a close watch on your health and shields. Soon the ground will flatten out and there will be a large structure to the right. There are also two Hunters. If you still have your Pistol (if you don't, there is one just a couple steps ahead), then a couple shot to the back should be more than enough to kill them. If you are extremely accurate you can get to the last tree and shoot the Hunters right below the "ear" by the crown of the skull. This results in an instant incapacitation, but is not recommended for any but the sharpest of shooters.
If you start having troubles with the Hunters, grab one of the two Overshields close by them, but try to save one for later. After the Hunters are dead, some Jackals will arrive and try to kill you. Yeah, right. Pop a cap in them before continuing up the path. Pick up the other Overshield if your other one depleted. Thank goodness they don't deplete with time like the ones in the Multiplayer do. Further along is a group of mixed Covenant. Finish them off.
To the left of this structure there is a small narrow path leading to the inside of another structure. There are a couple Grunts here, take them out. Next to the far entrance you can find three Overshields. You will probably need all of them, too. Head inside and you will see some Hunters. Take them out as you normally would, running back to pick up any Overshields once your current one depletes. After this, continue down the structure and press the button here. You will trigger a cinematic. The Golden Elite at the map room exits the now unlocked door, a plasma sword in hand.
If you did manage to get your Warthog through the gap, the stratagy is a bit different. When you get through, get out and kill the enemies in the first section so they can't stick you.
After unlocking the door leading to the Map Room, several invisible Elites creep up onto your location…
After pressing the button, head back up to find some invisible Elites. That's somewhat of an oxymoron, but whatever. Take them out and head outside. Pick up an Overshield if you need it and head down the "path" to the right. You will now be back on the beach.
Kill some grunts and jackals that are on the beach. You may find Bravo 022 crashed and some marines got killed. They left you more ammo and rocket launcher. It doesn't matter if you need it. Since you can only carry 2 weapons.
Run or ride back to the place where you got the warthog from Forehammer. 2 more marines will occupy the passenger and gunner seats. Ride in and go to the place where the map room is. 3 or 4 jackals will be protecting it plus 2 more hunters. Try to overrun them while your marines try to kill them by shooting.
CAUTION:The hunters have fuel rod guns right? So be careful when trying this with a warthog or by yourself. Your shield might wear off by 1 shot and a very few health bars vanish. Go inside and walk through the Locked-door-thats-now-open. The next part begins.
Note: Where did that Golden Elite go? Maybe he retreated or something.....
You might see the cutscene where MC is walking through the right hallway and looks. He kicks a loose piece that falls almost endlessly. He looks up....He looks down or the opposite.
Turn back and there is an Elite that is facing away from you. Give yourself a chance of hitting him in the back by meleeing him.Shoot the rest of the covenant and go through the door. A few jackals and another pair of hunters are on this floor. Kill them and if you are lucky, throw a plasma grenade or 2 on a hunter. He will not get killed but that extra damage will help you. Once they're all dead,earn the time of making your ammo full. Next room is empty and thats the part where forehammer tries to kill the covenant on their sight. The Sergant marine needs some help.Cortana contacts him to see if they can destroy them inside the building. Sergant whoever it is, is trying to hold them off and tells MC to find the cartographer and fast!
There are 2 doors and the left door has an active camouflague. Good if you like it sneaky.Kill all covenant in the room. You are halfway done now. Just kill the jackals and listen what cortana has to say. After the cutscene is over, this is the part where you like, you have to go backwards meaning you have to go up to surface. Cool music will play during this part. A few enemies know you got your dirty hands on the map room and gets lots of desire to kill you! Kill them and once you're almost to the surface, the golden elite will be there.
Now if you kept that rocket launcher, try to shoot him with one. Otherwise, use a plasma grenade or kill him with your bare guns with bare ammo. Now go back to the surface. A dropship with its gunner, code-named "Shade", will appear outside + some invisible elites. Wait for a while for it to fly away. The pelican will follow. Go inside. The cutscene will show the pelican leaving and forehammer is surprised at cortana when she shows that the coordinates are underground. She tells about what's going to happen when they kill the covenant inside the shaft.
Congratulations! You completed The Silent Cartographer level!