Our two main characters are Louise Baltimore, who lives in the distant future, and Bill Smith, who is an air crash investigator in our time (or what was "our time" when Varley wrote this novel in 1983). Their descriptions of events are intertwined, one chapter after another. Louise is an ancient but still beautiful 27 years old from what she refers to as "The Last Age," and a "snatch team leader." She and her team use a time machine they don't fully understand to go back to an incipient terminal air crash in the current day, where they pull all the "goats" (as they call them - the passengers) from the plane and replace them with already dead bodies. When the crash occurs, they have the still alive people, and hopefully no one notices the switch as that would create a time paradox. Bill Smith is 40(?) and a heavy drinker, the lead investigator of the two most recent air crashes that Louise and her team have harvested. But he begins to see anomalies.
The story is fairly well written, and the characters are well drawn and memorable. The ideas involved are ... a little bizarre even by science fiction standards. The ending inevitably involves a twist that's the result of a paradox (it is, after all, a time travel story). But Varley springs another twist on us in the last four or five pages that I felt was both dumb and over the top: let's just say he suddenly gets significantly religious despite having given no warning during the book. So a passable story with an ending that had me thoroughly unimpressed.