From Halopedia, the Halo wiki
In 2558, a series of large-scale attacks occurred on five human colonies. ONI was able to secure four of the sites but the fifth on the colony Conrad's Point fell into the control of the New Colonial Alliance. Reibach was tasked with coordinating the extraction of Commander Maya Sankar, a student of Reibach's during basic training who now works as an undercover operative who infiltrates insurrectionist groups under the codename "FERO". A squad of ODSTs were sent in to extract Sankar, killing 26 insurrectionists and wounding 41 in the process. When on the extraction ship, Reibach contacted her and told her she was being transported to ONI's Midnight Facility to be briefed by him.
When Sankar arrived at Midnight, Reibach showed her videos of the destruction on the five colonies and briefed her on her new mission to gather intel on the unknown attacker by infiltrating the NCA on Conrad's Point. Reibach then clasped an NCA pin on Sankar's lapel which allowed her to communicate with the AI Black-Box who would be helping her on the mission.
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