Twenty-five hundred scientists have been herded into an isolated site in the Nevada desert. A neutrino message of extraterrestrial origin has been received and the scientists, under the surveillance of the Pentagon, labor on His Master's Voice, the secret program set up to decipher the transmission. Among them is Peter Hogarth, an eminent mathematician. When the project reaches a stalemate, Hogarth pursues clandestine research into the classified TX Effect--another secret breakthrough. But when he discovers, to his horror, that the TX Effect could lead to the construction of a fission bomb, Hogarth decides such knowledge must not be allowed to fall into the hands of the military.