Pamela Cutler joined the Army after her father's death, and has risen to the rank of General. She has now been assigned to Snowcap Tracking Station, where scientists are working on a project named FLIPback, the human race's defense against the reversal of the Earth's magnetic polarity. In the event of such a shift, FLIPback will do just what its name suggests. Under Cutler's strict discipline, the project gets back on schedule - just on time, for the crew finds that true south is shifting out of position and realises that the reversal could occur within the year. While celebrating the successful completion of their work, Cutler finally gets to ask Lieutenant Hilliard what happened at Snowcap twenty years ago. He tells her what he's never told anyone before; about finding the remains of men in crumbling metal armour, and a spaceship which appeared to be falling apart and which had vanished by the time he got back to the landing site. He has never learned the whole truth; all he heard, after the fact, was that someone called “the Doctor” saved the world and then disappeared.