History
Friendship was the code name given to a facility located in Antarctica built by the United States in conjunction with the USSR in the 1960s. It remained abandoned for a long period of time until S.H.I.E.L.D. decided to upgrade it to meet their needs and use it as an outpost.
As a S.H.I.E.L.D. base, Friendship serve the purpose to act as the organization's ultimate fail-safe agaist being overrun. It played a key role in maintaining the integrity of the organization, storing data and controlling communication pipelines and transport worldwide. The facility was powered by a controlled nuclear reactor.
Indoors
Friendship was targeted by the new Headmistres of the Dark Room and her pupils, who attacked the outpost in order to turn on its self-destruct mechanism. Said mechanism had to be activated by a set of five keys, each carried independently by a member of the staff. A sixth false key was also guarded by an agent, though no member of the staff knew which one was it, thus all six keys were needed to ensure the self-destruct mechanism would be triggered.
Having caught notice of the Headmistress' plan, Black Widow infiltrated the base to stop her. She managed to retrieve all six keys after they had been stolen by six different pupils, but the Headmistress managed to steal them back and begin the self-destruct activation.[1]