The Storm (Level)

The Storm is the fourth campaign mission of Halo 3.

Upon completing it on the Normal, Heroic, or Legendary difficulties, the player will earn the "Assault" achievement and 30 Gamerpoints.

Background
It begins with UNSC Warthog convoy moving to Voi, whose objective is to punch through the Covenant Loyalist anti-aircraft defenses that surround the Ark and allow Commander Miranda Keyes to pass through unscathed to the Ark. Meanwhile, SPARTAN-117 leads a dozen UNSC Marines mounted on Mongooses and other ground attack vehicles to down a pursuing Covenant Scarab walker with the assistance of airborne Banshee and Hornet atmospheric attack craft.

Shortly afterwards, John-117 and his men charge an anti-aircraft emplacement that is mounted on the cliffs around the Ark, controlling the nearby airspace and preventing Miranda Keyes from passing. It is defended by a heavy contingent of Covenant Loyalist warriors, including high-ranking and powerful Brutes (including a Brute Chieftain armed with a Gravity Hammer) and a pair of Hunters. After defeating the garrison, the UNSC forces hit the emplacement on its weak spot, disabling it, and allowing Commander Keyes to slip past.