Scott Farley was a Boston man. He might not have been born there, but he was accustomed to the culture and had fit in like a glove. He loved Boston, almost as much as he loved his dog, but the last few months, he felt as though something was off. It wasn’t a sudden change, more like a slow creeping sensation, as if something was approaching.

He woke up the morning of March 5th in a cold sweat. He...