When the very notions of fact and history hang in the balance, is the world ready to embrace the hardest truth of all, that we are not alone in the universe? When John and Lisa receive a repeating pulse from another world at the mountaintop research center where they work, they realize that it is not simply false data, it is far too regular and enduring. Suddenly the long-awaited possibility of extraterrestrial life seems imminently plausible.