Horn of Abolition
From Halopedia, the Halo wiki
The Master Chief attacks the Horn of Abolition in order to destroy a vital communications array.
The Chief approaches the Horn of Abolition.
The Chief enters the compound. Alarms begin to blare. Security gates are raised.
The Chief engages the Banished troops guarding the Horn. An Unggoy officer shouts orders over a loudspeaker.
The Chief finds the building that holds the lockdown controls. The doors are sealed, so he enters through an opening in the roof. After eliminating the Banished personnel inside, he lifts the facility's lockdown.
A Phantom arrives and deploys enemy reinforcements.
The Chief fights his way to the Horn's control center, which the comms array is mounted on top of. Inside, he encounters a Sangheili Warlord, as well as a pair of ceiling-mounted automated defense turrets. He defeats these enemies and then proceeds to access the main control console.
The Chief heads back outside and engages the Banished reinforcements.
The Chief eliminates the majority of the reinforcements.
Additional enemy reinforcements arrive. The Chief fights them off as he begins targeting the array's now exposed power cells.
The Chief destroys one of the power cells.
The Chief destroys another power cell.
Banished drop pods are deployed and another Phantom arrives, delivering more enemy troops.
The Chief destroys a third power cell.
The Chief destroys the fourth and final power cell.
Mission is completed.