"Hydra Lives!"
Fury subjects himself to a highly-dangerous test in order to prove that an atomic missile can be detonated long-distance by a sonic weapon-- which S.H.I.E.L.D. believes HYDRA has their hands on.
While both he and Dugan are recovering from injuries, he looks into a mysterious Mexican millionaire, "Don Cabellero", who, on the urging of an undercover S.H.I.E.L.D. man, invites Fury to a grand party he's holding in the ancient ruins of Karnopolis, in the Sahara Desert.
Caballero is merely a disguise for the new Supreme Hydra, who knew the man who made the suggestion was a spy all along. Senator Dudley, who earlier appeared to know nothing about HYDRA, later turns out to have helped Fury in setting up the meeting.
After surprising Sitwell with the news that he is going, Fury then puts Sitwell in command while he's gone. Just then, a sonic boom shakes the HQ, as the "Overkill Horn" is being tested.