Harvest campaign

The Third Battle of Harvest was an engagement during the Human-Covenant War when the Covenant attacked Harvest again in the hope of securing a Forerunner artifact buried under the planet's north pole.

The battle
On January 6th, 2531, Admiral Preston Cole received a message from Commander Orez of ONI. Orez informed Cole that the Destroyer had repelled newly arrived Covenant warships in the Epsilon Indi System.

The Spirit of Fire was chosen by Cole due to it's role as a "support ship" rather than a warship. The "SoF" arrived at the system three days after the Prophecy sent their message.

Upon their arrival, Serena analyzed the Prophecy and reported that the ships nuclear reactor was damaged and was releasing harmful doses of radiation throughout the ship.

Serena also guessed that the ONI prowler that reported the battle to HQ was present at the time but did not make any attempt to stop it.

The SoF attempted to draw the Covenant away from the Prophecy and the Spirits dropships by using it's MAC gun and HAVOK Nuclear Warheads.

Fire Team Lima, commanded by Sergeant Forge, made it inside the ship. The team split up with Lima-One (Forge) heading for the NAV room and the rest of Lima searching for survivors. Serena noted to Forge through his visor that the ships AI "FitzGibbon" may have gone rampant.

Forge was originally denied access to the NAV room by FitzGibbon due to misconduct in his service record. After Forge reminded him of the Covenant borders, FitzGibbon gladly allowed him entrance into the NAV room to purge the data. FitzGibbon then activated a three-minute self-destruct timer and informed Forge his team was in Bay 2.

Upon his arrival at Bay 2, the team quickly evacuated with at least two of the UNSC Prophecy's crew. After arriving back on the Spirit, the survivors were taken to the Med. bay, where Serena informed Forge that the radiation inflicted onto the Prophecy's crew was too severe and that they would certainly die.

After the threat in space was destroyed, ONI kidnapped civilian scientist Ellen Anders shortly after a seminar on intelligent life that once existed on the planets Cote D'Azure, Bliss and Onyx. ONI wanted her to decipher a Covenant message written in Forerunner symbols. Anders was then sent to the UNSC Spirit of Fire via the UNSC Last Gleaming.

Upon her investigation, she concluded that the message meant that "treasure" (Relics) were to be found, but hidden (from the Humans). Shorty thereafter, Anders scanned the northern polar region of Harvest, concluding that there was a structure under the ice.

Ground battle
Sergeant Forge was ordered by Cutter to report to Alpha Base and repair it. Upon Alpha Base's re-entering into service, the growing military presence made an assault on the Covenant defenders of the structure.

Upon capturing the structure, Anders opened up a holographic map of the nearby systems. Several Sangheili disengaged their Active Camouflage and attacked Forge's group. Two Grizzlies were dropped in to help Forge escape from the Spirit of Fire. Upon their safe return to the Spirit, the ship left the system to follow the Covenant.

Aftermath
The information gained by the Covenant from the Forerunner structure led them to the UNSC colony Arcadia. Anders was drawn to the same planet after examining the artifact. The Covenant attacked Arcadia on February 9th, 2531, and the Spirit of Fire followed.