After the Battle of the Ark, a UNSC Pelican dropship crash lands on Thessia. Two ODSTs survive the crash and make contact with primitive Asari. Ninety thousand years later, Liara T'Soni discovers a strange looking aircraft and Human remains in an ancient cave burial chamber. The discovery she makes will take the Asari on a journey to discover their true lineage.

36 years have passed since the end of the First Contact War after humanity achieved a costly victory against the Citadel Council. Now humanity struggles to maintain control of its status as the sole galactic superpower fighting off Resistance and Internal Struggle. Meanwhile Dark Forces are at work seeking to quicken humanity's downfall and plunge the galaxy into chaos.