By the time they got there,Master Chief and Cortana meets with Sergeant Avery Johnson and Miranda Keyes,daughter of the late Captain Jacob. They discovered that they are being watched by the Elite. Then,the Covenant ambushed them while the Elites open fire. One of the Soldiers gets killed by the Covenant before he gets shot one of the Elites.
The Elite Commander,Arbiter reveals that the Covenant are the followers of their leaders,the High Prophets Truth,Regret,and Mercy,who are planning to using Halo as a weapon. They contact more Fleets. The Soldiers are being attack by Parasites called the Flood and some of them gets turn into one. They are saved by the AI 343 Guilty Spark,who had Halo's caretaker.
The Soldiers gets captured by the Covenant led by the Chieftain,Tartarus. Master Chief and Arbiter manage to reach them. The Flood attacks the Soldiers and the Covenant. Master Chief and Arbiter helped Johnson and Keyes escape as the Gravemind kills Mercy. Master Chief,Arbiter,and Guilty Spark are being held captive. Gravemind reveals that Arbiter's real name is Thel 'Vadam,who rebelled against the Covenants.
Johnson and Keyes fled to the Fleet where Tartarus and the Covenants attack. Master Chief,Arbiter,and Guilty Spark quickly escape and rushed towards the Ship. Tartarus kills Keyes and wounded Johnson. Two of the Covenant Ships are about to launch for earth,but Johnson manage to crash to collide one with the fleet before dying. The other ship with Truth inside escapes. Cortana learns of the Ring's whereabouts. Master Chief and Arbiter head towards the Ring while the Soldiers evacuate.
They are Confronted by Tartarus,who overpowered Arbiter. Master Chief has disarmed Tartarus and decapitates him with Arbiter's Energy Sword. They later confronts Regret,who tells them that the Covenants will never stop. Arbiter fatally stabs him to death. Master Chief activates the ring,causing it to self destruct. As they tried to escape,the force of Halo's blast causes the slipspace portal to collapse,resulting in only the front half of Forward Unto Dawn,carrying the Arbiter,making it back to Earth.
The Arbiter informs Lord Hood of the Covenants invasion and the disappearnce of Master Chief and Cortana. They must prepare the Soldiers and the Elites to prepare for the attack on the Covenants. In Space,Master Chief was in Crypsleep on the other half of the ship where he is awaken by Cortana.