Spartan Noble Team discovered a large Covenant Strike force the night prior, and the UNSC responded with a massive ground and air based counterattack the following morning. The overall goal of the UNSC was to blitz the Covenant Strike Force before the rest of the Covenant Fleet arrived, preventing any solid Covenant foot hold on Reach.
The main target for the UNSC counterattack was to take out the EMP spires located along the valley ridge. It is important to note that the UNSC did not know what the main purpose of the spires were upon attacking. Noble Team led the attack on Spire One, deactivating the EMP shield. This allowed the UNSC air support to destroy Spire One.
A massive UNSC force stormed the Viery plains towards the Covenant-occupied site, attempting to reclaim the land and eliminate all Covenant presences from Reach. Noble Team assisted the UNSC assault, with Noble Six and Kat-B320 via Warthog while Jorge-052 and Carter-A259 provided support from their Falcon.
The assault was soon confronted by heavy Covenant units, which officially initiated the Battle of Viery. Six and Kat avoided the onslaught by proceeding to their objective via bridge access, which was destroyed by Covenant mortars. Successfully making to the other side, the two Spartans continued to the Spire and eliminated Covenant forces while en route to the first anti-air emplacement. The Spartans then destroyed the Covenant anti-air emplacement, allowing for an air strike against Scarabs. Six and Two then headed to the BXR Mining Facility to assist Army forces in the area, including taking down a high-value Elite Zealot. Six and Kat then moved on to destroy another Covenant anti-air battery, after which Six joined Jorge and rode a Falcon towards the Spire site. With no other alternatives of entering the Spire site, the Falcon ran through the electromagnetic shields emitted by the Spire structure and crashed landed, killing everyone but Jorge and Noble Six. The pair continued fighting their way into the structure, with Six managed to deactivate the structure's shielding system. Cleared of defenses, the UNSC called in a MAC strike executed by the UNSC Grafton.
The spire's purpose was soon realized as a cloaking device for a CSO-class supercarrier in low orbit above Reach. Upon being discovered, the Covenant Supercarrier proceeded to obliterate the attacking UNSC forces, destroying the UNSC heavy frigate, Grafton with one of its energy projectors, and forcing Noble Team to retreat from the battlefield, the Supercarrier then retreated into Covenant held space in orbit above Reach.