The Mighty Avengers Vol. 1 (2007-2010) #6

Plot

The Unspoken speaks — and a world trembles! The Inhumans recently escaped to the stars to fight the War of Kings, leaving behind a secret that will consume the world in terror. Find out the true nature of this dark, terrible secret — and why, for centuries, it has been left unspoken! Join Avengers Hank Pym and Clint Barton as they lead a cavalcade of Earth's Mightiest Heroes — including Hercules, Quicksilver, US Agent, Jocasta and the Young Avengers against the kind of world-ending calamity that only they can handle!

Collecting MIGHTY AVENGERS #27-31.