When you get to the objective marker, there will be some Knights here but they'll immediately teleport away. Investigate the bodies and, if you want, take the DMR, which is a handy long-range weapon.
As you press forward through the jungle, you'll be ambushed by Crawlers, Knights and Watchers.
Eventually you'll come across a soldier being held up by a Knight. After they kill each other, pick up what the soldier dropped.
Now you can use Promethean Vision! It's a kind of cool looking x-ray vision power that shows where nearby enemies are. Use it to take down the Prometheans ahead.
Head forward, up this ramp, and head toward the objective marker.
Review the next IFF tag, then head forward to be attacked by more Crawlers, Watchers, and Knights that spawn sentry turrets.
Finally, after surviving tons of ambushes, you'll arrive at your objective. Check the IFF tag and watch the cutscene.
Head forward with your new allies and fight off the Prometheans that attack you.
Continue your trek through the jungle, fighting off Prometheans as you go, until you reach the friendly UNSC forces.
Help the soldiers fight off the Promethean onslaught. Knights, Crawlers, Watchers, Promethean turrets, lots of fun!
Push your way up the hill to the doors, and insert Cortana into this console so she can open the doors.
You'll have to hold off Prometheans for a few minutes while she works her magic on the doors. In the meantime, get on the turret and let 'er rip!
After what seems like an eternity, she'll get the doors open for you. Head through with your teammates and follow the dark corridor.
Oh good, Covenant and Prometheans are working together now! Because your job was just too easy, right? There's a rail gun ahead by those crates to make your life a little easier against the overwhelming forces.
When they're all finally gone, jump aboard the Pelican and fly back to the Infinity.
After getting off the Pelican, run to your right and grab the Scorpion tank just sitting there all by its lonesome. Enjoy yourself while you move forward and obliterate the Covenant that attack you!
Along the way, Wraiths and Ghosts will attack you. Pfft whatever, you have a Scorpion. Not happening. Do watch out for the floating scout towers to the sides though, they have fuel rod cannons that can hurt you pretty bad.
Drive your Scorpion into the objective marker, and the elevator will take you up into the ship.
It's a mess in here. Grunts, Jackals, Elites, Hunters...again, Scorpion tank. Once you're past them, Captain Del Rio will speak to you and tell you to head up and take a Mantis.
Head out of your Scorpion tank and through the maintenance causeway. I know, it hurts to leave the tank.
Activate the console, and...
Suddenly you forgot about the tank, huh? Get in!
Destroy the door in front of you, and again enjoy mowing down all the Covenant and Prometheans that get in your way.
You'll eventually come to an elevator. Take out the Covenant inside of it and it will take your Mantis up to the outer hull.
Out here, you'll have to destroy 3 Covenant jamming devices, which will be marked. While you're out here, try to take down the Phantoms flying around before they drop off more Covenant for you to deal with.
Once all 3 are destroyed, get out of the Mantis and activate this console to activate the MAC controls.
That's it for this mission! Off to take down Requiem's gravity well.