In analyzing signals collected by the NASA Laser Interferometer Space Antenna (LISA), designed to detect gravity waves propagating through the space-time continuum from such natural events as supernovas, astrophysicist Tom McWade unexpectedly discovers that beings on another planet are trying to communicate with the residents of planet Earth. The United States launches a secret program to build a gravity wave communication station, in a near-Earth solar orbit. The gravity wave station enables nearly instantaneous wide bandwidth communications between humans and the far more scientifically and technologically advanced tellerians, residents of planet Azura, . When Tom is directed by the President of the United States to accompany his twin brother Ted, a Catholic priest, to the Vatican, and reveal the existence of the tellerians to an international gathering of religious leaders, emotions and events quickly spiral out of control. Driven by the dream that he might one day be elected Pope, Ted becomes the central figure in a scheme to gain access to the gravity communicator, and use knowledge secretly obtained from the Tellerians to increase and secure power for the Roman Catholic Church. Tom is equally determined to use his discovery of the Tellerians to help humans conquer their irrational superstitions and religious myths, and move beyond persecuting, killing, and waging war on one another for differences in beliefs. Only time will tell which of the brothers will prevail
