When Ralph Underhill, a researcher at MIT in Boston, hears a knock at the door that day, he opens it expecting to see his ex-girlfriend, Emily Payne, who has come to collect her things and move out of his house and his life. Instead, it’s his co-worker Henry Saulman, who has been gravely injured and collapses in front of him. Before passing out, Henry reveals an amazing secret: the lab computer has come up with the next prime number containing only the digits 4 and 7 in its huge sequence of numbers. It seems to be some kind of encoded message from a higher entity wishing to communicate with humankind. At the same time, extraordinary phenomena and natural disasters rock the planet, while Ralph and Emily unite in their attempt to solve the mystery. While everything seems to point to the coming of Judgment Day, some are concerned that something much worse is about to happen.

Kastaniotis, 2008, p. 576