Halo 3: ODST - Part 03 - Xbox 360.

ODST takes place in the 26th century when humans under the command of the United Nations Space Command (UNSC) are locked in a war with a theocratic alliance of alien races known as the Covenant. During the events of the 2004 video game Halo 2, the Covenant discover the location of Earth and launch an assault on the city of New Mombasa in Africa. Though the UNSC manages to repel most of the fleet, a large ship hovers over the city, depositing an invasion force. The ship eventually retreats via a slipspace jump, creating a massive shockwave. While the rest of Halo 2's storyline follows the ship to an ancient installation similar to the first Halo, ODST focuses on the aftermath of the shockwave, while the Covenant still occupy the city.