Raid on Ivanoff Station

The Raid on Ivanoff Station took place in 2557 after the Didact's ship, Mantle's Approach arrived at Ivanoff Station to retrieve the Composer.

Background
The Didact, an ancient Promethean general, had been released from imprisonment on Requiem and planned to use a device known as the Composer to digitize humanity, preventing them from threatening Forerunner dominance. With Captain Del Rio of the dismissing this threat and having the ship leave Requiem, Master Chief John-117 was left to pursue the Didact alone with his increasingly rampant AI, Cortana. The Master Chief's attempts to stop the Didact from leaving Requiem were unsuccessful, however, and the Promethean escaped aboard his flagship, Mantle's Approach. However, John-117 and Cortana stowed away on one of the Covenant Lich deployment craft accompanying the Didact's ship as it entered slipspace, headed for the Composer's location.

Battle
The Master Chief followed the Didact to Ivanoff Station, a UNSC research base orbiting Installation 03, and the Composer's resting place. Dr. Sandra Tillson, lead researcher aboard the base, helped guide John to the artifact amidst a swarm of Covenant attackers. Despite the Spartan reaching the artifact first and planning to destroy it with one of the excavation-grade HAVOK nuclear warheads stored in the base, the Didact successfully obtained the Composer, tearing it out of the station's hull with a gravity beam. Testing the device, the Composer burned the crew of the station and the Covenant troops to ash, assimilating their consciousnesses to digital form. The Master Chief's genetic enhancements provided by the Librarian on Requiem rendered him immune to the device's effects, leaving him as the only survivor on the station.

Aftermath
With the Composer in the Didact's possession, the Forerunner was poised to deal a deathblow to Earth, and by extension humanity. However, John-117 followed him into slipspace aboard an F-41 Broadsword fighter, carrying a HAVOK warhead. Positioning his vessel in Earth's orbit, the Didact successfully fired the Composer on one city, but he was eventually defeated and his ship was destroyed by John-117, saving humanity from imminent genocide.

List of appearances

 * Halo 4