To provide some context first: This short was filmed as camera tests with Neill Blomkamp, who was at some point considered to do the HALO Movie. All you see here are basically just camera tests he did during his trial runs.
The year is 2552, and Gage has just been saved by the Rookie on the colony of New Jerusalem. Instead of letting the Rookie take him back, he forces him to listen to his story of the war, so that the Rookie won't make the same mistakes.
A vicious Asari mercenary will stop at nothing to recover an ancient Prothean artefact. The only person to stand in her way - an alliance ensign on one of her first missions.