The Pillar of Autumn wasn't the only ship that left Reach when the UNSC withdrew from the planet. The UNSC was desperate to find a planet to settle on where they can effectively hide from the covenant and recover from the near fatal blow they suffered on Reach. When the Hall of Heroes, a ship similar to the Pillar of Autumn only smaller, finds an unexplored planet away from the covenant empire, they
immediately launch a recon mission to confirm if the planet is habitable, Mikel Dakre and his ODST team find more than they bargained for.