The Second Battle of Meridian was a conflict between the colonists of Meridian funded by the Liang-Dortmund Corporation, the UNSC, and Prometheans under control of Cortana on October 25th, 2558. The battle began when the Guardian underneath the planet's crust was activated, causing severe damage to the nearby colony and mobilizing the Guardian's Promethean defenses. During the fighting, Spartan-II Blue Team arrived on the planet in an attempt to travel with the Guardian to Cortana's location, and Fireteam Osiris arrived later to try and detain Blue Team. Osiris managed to catch up to Blue Team, but were unable to stop them from getting on the Guardian and leaving to Genesis. Osiris was forced to evacuate the planet and human colony, which was severely damaged during the attack and transit of the Guardian through slipspace.