The year is 2525. At the start of the Human-Covenant war, the UNSC had located a small planet now known as "Lumoria." The UNSC had discovered architecture and animal wild life on the planet, that no one knew of. This planet was built by the Forerunners, they would later realize. A small research vessel was sent to Lumoria to study the new planet. Shortly there after, they were attacked by Covenant forces. The UNSC picked up a distress signal from the planet's surface. It was a message from one of the scientists. Their vessel was attacked by several covenant ships while he was studying the interiors of the new structures. The Endless Horizon, a small, stealthy UNSC frigate is sent in for a low-profile search and rescue mission.