Infinity (Halo 4 level)

Infinity is the fourth campaign level of Halo 4. Completing the level on any difficulty grants the player the Infinity achievement, while completing the level with no preventable Marine deaths on Heroic difficulty or harder unlocks the Bros to the Close achievement.

Summary
John-117 arrives at Infinity 's crash site to find UNSC forces overwhelmed by the Prometheans. After searching and following a few squads of Marines, John eventually meets Thomas Lasky and Commander Palmer. Captain Andrew Del Rio orders ground teams to return to Infinity to repel the attackers, but Lasky cannot clear an landing zone. He requests John-117 to clear an landing zone for the UNSC forces in the swamp. John-117 finds an area occupied by the Covenant remnant, who has joined the Promethean forces, and clears it for a landing zone.

John-117 is then taken by a Pelican to Infinity's crash site, where he, along with several Spartan-IVs, clear a path to Infinity 's hangar bay. Once he entered the ship, John-117 pilots a Mantis and heads through the service corridor to the top side of Infinity, where the Covenant remnant has set up three jammers to prevent the ship from firing her weapons at Didact and the Covenant remnant's battlecruisers. John destroys the jammers, and holds out until he can re-activate the Infinity's MAC cannon. With Infinity's weapons all firing at his Cryptum, Didact retreats after two Covenant battlecruisers are destroyed.

Trivia
The Halo 4 E3 2012 Stage Demo is a heavily modified version of this level.