This lack of drama surrounding the aliens' arrival helps keep Yesterday's Kin running smoothly. We meet Marianne Jenner, a geneticist whose research is of particular interest to our visitors, and her son, who is addicted to a drug called sugarcane that allows him to become a personality tourist, trying on random perspectives and personality traits while the drug is in his system. The novel is a family affair, but not in the overwrought faux-Spielberg style of Interstellar; Kress is excellent at keeping excessive sentimentality out of the story.
I don't want to give too much of Yesterday's Kin away; its pleasure is in its plot. Kress's primary interests of genetics and the end of the world are both involved, and the aliens are sufficiently alien, which is an important factor in a book like this. At less than two hundred pages, this is a book you should read as quickly as possible, preferably in one afternoon's sitting. The small size means that not every plot thread is inspected to its fullest (I would've liked to see sugarcane examined more closely; it's such a delightfully Philip K. Dick-style drug that it's a shame to see it squandered on a secondary plot) and that the reader is left with as many questions as when they picked the book up in the first place. But some people read science fiction because they want to investigate avenues of possibility on their own; Kress's fiction in general, and Yesterday's Kin in specific, is perfect for those readers. It's a book that asks its readers "what if?" and leaves them to wonder about what might be.