You're all rookie recruits for a brand new S.H.I.E.L.D. United under one director, the unit has become dedicated to keeping the world safe from influences that might shatter the fragile relative peace that has a tentative hold at the moment.
The problem is Hydra is scattered and desperate to keep what little remains of their organization. Small pockets are attempting to reorganize and with the Avengers and S.H.I.E.L.D. already stretched thin, you have to be pulled into the field earlier than Director Coulson would prefer. Good luck team, you're going to need it.