As the world fights against the COVID-19 pandemic, nuclear weapons have taken a backseat in most people’s minds. But for Global Strike Command (AFGSC)—the Air Force unit in control of two of the three legs of America’s nuclear triad—their mission remains top priority.

And it’s an unforgiving business. Nuclear deterrence requires extreme levels of readiness among pilots, maintenance crews, and security teams. Adversaries that don’t think the U.S. can respond with conventional bombing strikes or nukes could be emboldened to act aggressively.

But in a War of the Worlds-style twist, humanity’s most lethal weapons could be nullified by an organism that can’t even be seen. It’s up to the AFGSC to make sure that never happens.