Raid on Ivanoff Station

"You are a fool. Even now, your kind tinkers with the Composer in the shadow of the third ring. Children and fire, who disregard the welfare of the galaxy."

- The Didact

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
Following the Didact through slipspace aboard a Covenant Lich, the Master Chief and Cortana are surprised to discover that the Didact takes them to Installation 03 which Cortana recognizes as the place where found the coordinates to Requiem. The two quickly realize that the Didact is not headed towards the Halo ring but rather the nearby Ivanoff Station. The Master Chief hijacks the Lich and contacts Doctor Sandra Tillson on the station who is relieved to hear him. However, Cortana's rampancy gets the better of her and she crashes the Lich into the station instead of landing in it.

After regaining consciousness, the Master Chief contacts Tillson to begin evacuation procedures, but is warned that the Covenant have already taken over Ivanoff Station's landing bays. The Master Chief promises to do what he can to clear an evac route on his way to Tillson and makes his way through the station. Arriving in Landing Bay 7, the Master Chief finds the station's forces desperately defending it against an unending stream of Phantoms. Using the Harbormaster's control station, the Master Chief erects a shield that prevents more Covenant from entering and clears the landing bay of enemy forces. Once the bay is clear, the Master Chief resumes fighting through the station as the Didact scans it. Cortana realizes that the Didact only knows that the Composer is on the station but not where it is and is thus looking for it. The Master Chief fights his way to the station's control room which is under attack by a pair of Hunters. The Master Chief kills the Hunters and enters an elevator to meet with Tillson.

Tillson starts the elevator down and the Master Chief explains that the Forerunner artifact the Ivanoff scientists excavated is a weapon that the Didact wants back. Tillson warns the Master Chief that the Composer can't be moved, it having taken three months and "the biggest starship the UNSC could throw at it" to move the Composer to Ivanoff Station in the first place. Recognizing this, the Master Chief has Tillson give Cortana access to the station's supply manifests so they can find a way to destroy the Composer and deny it to the Didact. Cortana locates seven excavation grade HAVOK tactical nuclear weapons in the station's manifest and Tillson protests using them to destroy the Composer due to the years of work the scientists have invested in studying it. When the Master Chief refuses to relent, Tillson reluctantly agrees to have the nukes primed for remote detonation and to continue the evacuation.

The Master Chief makes his way to the atrium where the Composer is stored only to be informed that the Covenant shot down the station's first evac shuttle. Recognizing that the station has outer turrets, Cortana instructs the Master Chief to take her to the controls so she can reprogram the turrets to cover the station's evacuation. The Master Chief reenters the main parts of the station and resumes fighting through the various corridors, facing Covenant boarding parties at two sets of airlocks as the Didact keeps scanning the station for the Composer. Finally, the Master Chief reaches the control area and after eliminating the two cloaked Sangheili Zealots located there, inserts Cortana into the control systems. Cortana, despite her rampancy growing ever worse, is able to activate Ivanoff Station's Onager cannons and have them fire on the Covenant ships besieging the station. The Master Chief alerts Tillson who promises to issue the final evac orders and instructs him to meet her and her crew back on the upper platform where they will help the Master Chief get their nuke to the Composer.

Fighting his way back to the atrium, the Master Chief discovers that Covenant forces have found the Composer. To keep the Covenant from warning the Didact, the Master Chief takes control of a nearby Mantis and engages Covenant forces made up of Ghosts, Wraiths, Banshees, Phantoms and ground troops dropped by the Phantoms. The Master Chief contacts Tillson for his nuke, but is warned that its not ready yet. After multiple waves of enemies, the surviving Covenant forces retreat from the atrium. Unable to raise Tillson, the Master Chief makes his way to a nearby elevator to find her. As the elevator takes him higher into the station, the Didact finally locates the Composer and uses Mantle's Approach's tractor beam to remove it from the station, removing the roof of the atrium entirely and stunning Cortana so much in her rampant state that the Master Chief has to help her focus again to get her to find Tillson.

Reaching Tillson, the Master Chief warns her that the Didact got the Composer and that she needs to evac her remaining people. The Master Chief inserts Cortana into the station's systems and orders her to find something that can carry a payload. Noticing the Composer charging, the Master Chief asks Cortana to reactivate the station's defenses, but she is unable to. The Didact fires the Composer at the station, digitizing everyone aboard except the Master Chief who was rendered immune by the Librarian.

Aftermath
Following the digitization of Ivanoff Station's personnel, the Master Chief is awoken to a traumatized Cortana and piles of ashes. The Master Chief tells Cortana that its not over as more people will die if they can't stop the Didact from reaching Earth with the Composer. Cortana is able to pull herself together and spin up one of the station's F-41 Broadswords located in Hanger C-11. Despite their losses, the Master Chief assures Cortana that the fight isn't over yet. With the Broadsword they take armed with one of Ivanoff Station's HAVOK tactical nuclear weapons, the Master Chief follows the Didact through slipspace to Earth where he attempts to digitize the population of humanity's homeworld as he did Ivanoff Station. However, the Master Chief is able to board the Didact's ship, Mantle's Approach and destroy it and the Composer with the nuclear weapon he got from Ivanoff Station, preventing the Didact from digitizing more than the population of New Phoenix.

A handful of the Ivanoff's personnel managed to escape into the nearby asteroid field and were later saved by search and rescue teams.

List of appearances

 * Halo 4
 * Halo: Escalation