The novel describes the eventful epic journey of the narrator, which seems to begin as a story of Cold War espionage but, involving life forces beyond Earth, finally leads to Jupiter.

Peter, the narrator of the story, lives in Idaho, USA; he is a student of Byzantine art and a part-time ski instructor.

Telling Peter to leave and return, he turns up the battery's power and there is a huge explosion which produces a crater and melts the surrounding snow.

After a difficult crossing of the pass, he finds a mountain hut and meets Edelstam, a physicist whom he once taught to ski back in Idaho; he must be the man Alex mentioned, and presumably an Outlander.

In Turkey, Peter is picked up by local people in a truck; there is an explosion, seemingly caused by his replacement pack, and he later finds himself in hospital in Erzerum.

After eventually giving a muddled account of his contacts, he is given an injection which is meant to kill him; however he is revived and rescued from a coffin by another Outlander, who takes him to a farm to recover.

From the Outlander space terminal in Anatolia he travels with other conference delegates to Mars; however on arrival he is unexpectedly transferred to another spaceship destined for Jupiter.

They are out of the plane of Jupiter's orbit so that they are never intercepted by another planet or asteroid; they are reflected to Earth, one directed to the Eastern Bloc and one to the West.