Scramble onboard Forerunner Dreadnought

In November 2552, towards the conclusion of the fall of High Charity, Spartan John-117 boarded the Forerunner Dreadnought in the center of the holy city during his pursuit of the Prophet of Truth shortly before he departed from High Charity, heading to Earth. Near Jupiter, John was contacted by Io Station, but maintains radio silence. Rampaging through the ship, he attempted to find the Prophet of Truth and assassinate him.

Background
The Prophet of Truth arrives in the Sol system aboard the Forerunner Dreadnought escorted by a Covenant fleet on November 8, 2552, and proceeds on course towards Earth at near-relativistic speeds. However, due to John-117's presence aboard the vessel, the ship's crew becomes preoccupied with finding and eliminating the Spartan.

Elsewhere in the Sol system
During the skirmish in the vessel, John-117 commandeers a Ghost and crashes it into a large congregation of Covenant troops. Wielding a pair of SMGs, the Spartan proceeds to tear into the surviving Covenant soldiers present, largely Unggoy and Kig-Yar. Eventually coming to a locked door, the Master Chief blows it up using a trio of frag grenades. On the other side, the Spartan was greeted by a larger group of Covenant, including a large pack of Jiralhanae. He engages the Covenant present, eliminating large numbers of them before a large bay door opens, revealing six Mgalekgolo. The massive aliens simultaneously open fire on the Chief with their assault cannons, incapacitating the Spartan. Covenant forces soon surround the prone Spartan, and a Jiralhanae War Chieftain begins to interrogate the Chief about the Key of Osanalan.

The Spartan manages to stick the War Chieftain with a plasma grenade, devastating the Covenant force in the corridor and leaving only a pair of Unggoy Minors alive while the Chief makes his escape. The Chief then continues his push through the ship, eventually arriving in a large chamber with the Prophet of Truth present. The Master Chief observes the Hierarch as he and his Jiralhanae Honor Guardsmen meet with a pack of Jiralhanae soldiers. The Spartan sets his sights on the Prophet, and levels a carbine at Truth.

Before the Spartan can take a shot, a Kig-Yar Sniper opens fire on him from behind. He falls and lands right in front of the Prophet and his Jiralhanae guards. He manages to take out the Kig-Yar Sniper and opens fire on the Prophet. While the Chief manages to get several shots at Truth, the Prophet is shielded by his gravity throne and he escapes behind a door as his Honor Guardsmen fall. The Chief is forced to confront dozens of Jiralhanae soldiers. After a pitched battle, the Spartan kills all of the Covenant forces.

Earth
Believing the Spartan to be dead, the Prophet of Truth orders the crew of the Forerunner Dreadnought to jump further in-system and enter Earth's atmosphere on November 17, 2552. When the ship arrived over Earth via slipspace, John-117 contacted Fleet Admiral Terrence Hood by indicating that he was aboard of the Covenant flagship while the Home Fleet that was facing its near-total destruction by the Jiralhanae Covenant fleets spearheaded by the Prophet of Truth originally attempted to target the "unknown" alien ship.

John, having failed in his attempt to assassinate the Prophet of Truth and take control of the Forerunner Dreadnought's trajectory, fights his way out of the Forerunner ship's airlock in another commandeered Ghost. On the surface of the Dreadnought, he is informed that the command ship holding the "key" is to be destroyed, and that he will be within the radius of the blast unless he takes immediate evasive maneuvers. He moves to another part of the Forerunner ship to avoid being caught in the blast's wake. The Master Chief is then ordered to find a way to return to Earth quickly.

List of appearances

 * Halo: Uprising