When a one-way time tunnel to Earth's distant past, specifically six million B.C., was discovered by folks on the Galactic Milieu, every misfit for light-years around hurried to pass through it. Each sought his own brand of happiness. But none could have guessed what awaited them. Not even in a million years. In the early twenty-second century, many humans are being born with psychic powers and are linked in a single galactic mind. Those without these powers--the misfits, undesirables, criminals, and radicals--have a choice: mental reprogramming or exile. Exile, voluntary or otherwise, takes them back six million years, to a time between the extinction of dinosaurs and the rise of Homo sapiens, and to a time of exotic surprises and unknown dangers.