Book excerpt: A secret city buried a mile under America is discovered through the leakage of Von Doom radiation--a type of energy emitted only by time-travel devices. The Secret Avengers hea underground to a weird metropolis forgotten for decades, because a time machine in the wrong hands is the worst kind of WMD imaginable. Then: MI:13 learns that people are being abducted from villages in the former Yugoslavia--but the British government refuses to act on it. Even the added strength of War Machine and Valkyrie cannot prepare the Secret Avengers for 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. There are people who would do that either to hold the planet ransome--or just to die knowing they took everyone else with them. And right now there are just three people--Steve Rogers, The Black Widow and Shang-Chi--between us and total annihilation, trapped on a space station in the No-Zone. COLLECTING: SECRET AVENGERS 16-21