Halo trilogy

The  is the unofficial name for the first trilogy of Halo games. The series began with Halo: Combat Evolved, which was released as Bungie's first Halo game in 2001.

Halo: Combat Evolved
The emerges out of Slipspace to find a huge ring — a "halo" floating in space. The main character, Master Chief Petty Officer John-117, is aboard the Pillar of Autumn when the ship comes under attack by the Covenant, an alliance of aliens and the arch-enemy of humanity. John-117 evacuates the doomed ship for the surface of Halo to protect the Autumn's artificial intelligence, Cortana. She carries highly sensitive military information, which would prove disastrous if she were captured by the Covenant. With the UNSC Marines by his side, Cortana providing direction, and his assault rifle ready and loaded, the Master Chief sets to finding out the mysteries of Halo and defeating the Covenant.

Halo 2
The game begins on High Charity, the mobile capital city of the Covenant. The former Supreme Commander of the Fleet of Particular Justice, Commander Thel 'Vadamee, is being tried before the High Council for his failure to protect Halo. Despite his insistence that the Flood hampered his abilities, the Hierarchs who lead the council, the High Prophets of Truth, Mercy, and Regret, deem him guilty of failing to protect the Sacred Ring. 'Vadamee is then stripped of his rank and branded with the Mark of Shame by Tartarus, the Chieftain of the Brutes.

Halo 3
On November 17th, 2552, two weeks after the events of Halo 2, John-117 crashes through Earth's atmosphere onto an east African jungle. After Sergeant Major Avery Junior Johnson rescues the "Chief," Thel 'Vadam and a handful of Marines, heads toward the extraction point. Covenant forces are sighted in the area and Johnson splits the group to reduce their chances of getting spotted. John-117 and Thel 'Vadam continue on their way to the extraction zone with the second squad, fighting off numerous Covenant troops in the process, but upon reaching the extraction zone, Avery Johnson's Pelican group consisting of two Pelicans, are ambushed and shot down by Banshees. Johnson and his men are then captured and taken prisoner by a number of Brutes led by a Brute Chieftain. John-117, Thel 'Vadam, and company fight their way through hordes of enemies and eventually rescue them, after which a Pelican piloted by "Hocus" arrives and picks them up.