Originally published as an interactive novel on computer disk in 1986, Portal is the story of an astronaut who returns to earth from a mysteriously aborted mission prematurely awakened from suspended animation. One hundred years have passed; animals and plants thrive, cities stand intact. Every human being however has disappeared.

With the help of a slowly-reviving computer network, the astronaut begins to piece together the events of the last century. He learns of the child prodigy Peter Devore, of a world orchestrated by stunning new technologies, and of Peter's race against time to unlock the secrets of the Portal.