Gregory and Frisk travels to Dimension-50, during the years of 2531, in January 1st, where they ended up on the planet, Arcadia, in the Procyon System. Soon after one month, and few days, the Covenant invades Arcadia. Gregory and Frisk assists the SPARTAN-II's defend the Civilians make it off planet in the Transport shuttles. Both Gregory and Frisk were given ODST Ballistic Battle Armor specifically worn by the ODST's.