Secret Avengers: Run The Mission, Don't Get Seen, Save The World

Collects Secret Avengers (2013) #16-21. A secret city buried a mile under America. A time machine in the wrong hands is the worst kind of WMD imaginable. The next level in bioterror. Plus: a can of matter the size of a football, mined from a broken universe, would be enough to turn the Earth into a sun. And the Secret Avengers are on the front line of it all.