Imagine you are stranded on a strange planet which is eternally light on one side and dark on the other. Professor Edmunds, a disgruntled, underappreciated, bitter genius existing in the dingy basements of UC Berkeley's Astronomy Department, experiences this very fate. 

Professor Edmunds, on that historic night in the UC Berkeley Astronomy Tower, did not only discover the Dark Planet - he discovered something much, much more. His discovery confirms his long-held, and largely-ridiculed, scientific speculation: that every soul on earth shares, somewhere in the universe, an exact replica - a biological duplicate - an Other. 

He feigns surprise during the discovery, because he has seen the truth, seen everything, through the eyes of another. For every you, there is, somewhere out there, another you - an Other you. 

With Ford, his delinquent son, in tow, along with a band of Wyand Corporation cyborgs, the party departs Earth, traveling to the mysterious Dark Planet. On the Dark Planet, there exist two civilizations. One is advanced and abundant, dwelling in the perpetual sunshine of the Light. The other, destitute and despairing, toils in the eternal twilight of the Dark. 

Crash-landing in the water on the Dark side of the Dark Planet, Edmunds, Ford, and the party find themselves marooned on a hellish island, a sinister site harboring horrific secrets and offering no escape. Meanwhile, on the Light side of the Dark Planet, rebellion brews, and the Emperor finds himself torn between safety and his search for truth, the truth which, like Edmunds, plagues him in his visions. 

Edmunds's arrival on the Dark Planet not only shatters every fundamental assumption of humanity regarding its place in the universe, but, also, it ruptures the delicate, deathly balance between the Light and the Dark.