Frequency (Unabridged‪)‬

An epidemic of suicides. A mystery buried in Jupiter's icy moon. A revelation for the ages.

The new novel from multimillion-copy international bestselling authors Douglas E. Richards and Joshua T. Calvert.

Dr. Alexandra Lennox, a brilliant neuropsychiatrist, rushes to the jungles of Colombia to investigate a terrifying surge in collective psychotic events—groups of healthy people suddenly gripped by visions, catatonia, and inexplicable mass suicides. Teaming with rugged ex-archaeologist Ethan Calloway, she braves treacherous territory to unravel the mystery as the death toll climbs. But the phenomenon is spreading fast. Can they stop it before it becomes a global catastrophe?

Meanwhile, half a billion miles away, Lieutenant Jason Crowe and three other NASA astronauts, on a clandestine mission to reach Jupiter’s ice moon Europa, discover something impossible: a perfectly geometric shaft in the ice pulsing with an artificial signal every 47.5 hours.