Microsoft officially announces Halo 4 during their E3 press conference, confirming the development by 343 Industries.
343 Industries announces the release date for Halo 4 set for November 6, 2012.
Halo 4 is officially released worldwide on Xbox 360, marking the start of a new saga for the Master Chief developed by 343 Industries.
The official launch trailer for Halo 4 is released, showcasing the game's story, enemies, and new gameplay mechanics.
A beta period is held giving players early access to Halo 4 multiplayer modes and gathering feedback for final adjustments.
The UNSC forward scout ship Forward Unto Dawn is reactivated to investigate a Forerunner signal detected in Requiem system.
The Forward Unto Dawn arrives in the Requiem system, a mysterious Forerunner planet emitting an unknown signal, beginning the mission's main events.
Cortana shows signs of rampancy, a condition leading to AI deterioration after extended operational time, adding urgency to the mission.
After being attacked by the Prometheans, the Forward Unto Dawn is split in half and crash lands on Requiem, stranding Master Chief and Cortana.
Master Chief begins combat operations against Promethean forces and Covenant remnants on Requiem to discover the nature of the planet's distress signal.
Master Chief discovers that the planet houses an ancient Forerunner device called the Composer, which can digitize and destroy biological life.
The Didact, a powerful Forerunner warrior, awakens and confronts Master Chief, revealing his plan to use the Composer against humanity.
Cortana sacrifices herself to save Master Chief from the Didact’s attack, marking a pivotal emotional moment and heightening stakes.
Master Chief successfully sabotages and prevents the activation of the Composer, stopping the Didact’s plan to digitize humanity.
Master Chief escapes Requiem aboard the abandoned Forward Unto Dawn and is rescued by a UNSC vessel, ending the mission.
