It's the early 22nd century and Earth is ravaged by a spreading, lethal inundation of radioactivity.  The World Council, unable to deal with the situation, gives way to the dictatorial Collective, a nebulous and arbitrary body of scientists and bureaucrats who, alone, possess the means to save what is left of humanity by choosing who will leave the dying planet in a massive, global 'Launch' - to a heretofore unknown 'Network' of orbiting space stations.

Now, a generation later, the human survivors of the Network cling to life in the face of a finite supply of food and energy.  But they may have found a way out - a Doorway through space.

Dr. Mariss Arlen Keppeler, whose father's particle emitter has proven to be the Key to this astral door, must now convince Newton Idris, the Network's autocratic Director and one-time rival of her father, and the rest of the 'suits and coats' (as she calls them) who rule the Network, to allow her to follow upon the heels of Alpha, the first crewed mission through the doorway.  That ship had been captained by her husband, Brayton, and has not been seen or heard from in eleven long months.

Resources are scant and finally Mariss is allowed to go - in only a one-man Scout - to find out what happened to Alpha and, if necessary, to complete its mission; to find another home for a humanity losing hope - beyond the Portal.