- There on the platform jutting out over the ocean, is the skull.

Follow this Halo: Reach walkthrough to find the hidden skull located on a platform jutting out over the ocean, detailing enemy encounters and strategic approaches.

Continue past the Arbiter's generator station and around the cliff face to reach the third generator station. If you are being hit from behind, spin the Hornet around and fly backwards while shooting at the attacking Banshee.

When you get near the third metal tower, you will encounter heavy anti-aircraft fire. Fly low and take out the two orange turrets, the Wraith, and the two AA tanks on either side. Once those are clear, Brutes will begin pouring out of the station; the Hornet can make short work of them. If you prefer to tackle this area on foot, a Fuel Rod Gun can be found in the forested areas on the right landing zone, behind a rock in a Covenant crate. You can also jump out of the Hornet from a high altitude, effectively paradropping into the area.

Head into the Forerunner structure to deactivate the third shield. Along the left side, a mess of drones will appear; have a pair of Spikers ready to neutralize them. Once they are gone, proceed to the middle lobby to battle Hunters. If you still have the Brute Hammer, use it on them. Otherwise, use the Fuel Rod Gun found back in the grassy area. When the area is clear, your Elite allies will crouch around the door you should enter. Advance up the ramps and battle the Brutes. To find TERMINAL 6 (t06), climb onto the beam elevator but do not go up; instead, jump across the darkened room to get the terminal. Jump back to the beam elevator and ride it up to the control room.

The generator control room is heavily guarded by Brutes, who have been upgraded with invisibility. Stay back in the first alcove, pop out to shoot passing invisible Brutes, and they will follow you back. Continue to shoot them one by one; they will follow you back to the alcove. Once all other Brutes are dealt with, confront the chieftain at the head of the room. Use your Hammer or the nearby Needlers.

After hitting the switch, the sky opens up, and a meteorite crashes through the window, bringing a ton of Flood into the generator room. Grab the plasma turret the Chieftain was carrying and eliminate the Flood. The Elite's ship lost its weapons systems but is stable. Miranda commands a focus on the Truth, dealing with the Flood later. Backtrack out of the base and onto the landing zone. Guilty Spark recommends exploring the meteorite crash site for damage to the Ark, but Miranda's plan to confront Truth first gains traction, leading you to breach the Profit Truth's Citadel. A fresh supply of vehicles is delivered; pick the tank unless you prefer more driving while your NPCs do the shooting.

Drive the tank through the snowy countryside. As you descend, the Halo 3 Love Theme builds. The Giant Forerunner structure glints in the dusk light. As you wind around the trail, shoot across the switchbacks to take out many of the vehicles before they get within range.

At the end of the path, two Hornets are provided for a fight against two Scarabs. You can take out a Scarab by jumping onto it and circling around to the shield core, or by shooting the large glowing weak point on its rear. If boarding, fly around it to shoot the Brutes that emerge and stand on its back. If attacking the rear, circle to the back and aim for the glowing weak point. Continue shooting the tail until the backside falls off, exposing the core that must be shot to implode the Scarab. While in your Hornet, maintain a distance from the Scarabs as they pack a punch up close. Repeat this for the second Scarab.

With the two Scarabs defeated, the Citadel's main defenses are down. The Covenant is holding Johnson captive and preparing to fire the rings. Proceed to the navigation icon, and Guilty Spark will activate the drawbridge. As Master Chief enters, Cortana returns. Inside the citadel, the Profit attempts to force Johnson to activate the Ring. Miranda crashes a Pelican into the command center, holding the Brute and Profit at gunpoint. The Profit shoots Miranda in the back with a Spiker. The Profit explains that humans were left by the Forerunners to activate the rings, making them the equivalent of a hidden key.