This novella has two complementary storylines, really: each relies on the other to give it more meaning and to create tension, although each could be a satisfying story on its own. One thread of the story isn’t SF at all, as such: it’s about family and belonging, knowing who you are and knowing who your family are. The other thread is fairly typical SF: an alien civilisation contact Earth saying that they are very close to humans, genetically, and that a disease that devastated them is coming toward Earth. So then there’s a scramble to find a cure or a vaccine, with plenty of secrets and inequalities in the relationships, etc, etc.
Where the two come together is in the customs of the aliens, which emphasise family, and one of the scientists from the humans, who has besides her interests in genetics a somewhat dysfunctional family. I’m not going to spoil the various twists in the story which weave the two threads together, because I found it fairly predictable even without hints!
My main feeling is one that I’ve had before with Kress’ writing: I didn’t really feel the emotions deeply. It seemed like I should, but there was something distant about the characters. I could relate to them fine, but I almost didn’t believe their emotional moments, their turmoil. It was quite weird, intellectually recognising each reaction and knowing it was appropriate for the situation, and yet somehow not feeling as if it was real for the character.
Overall, I liked the ideas and the way the two threads work together, and though I’d begun to expect the twist, I did enjoy the way it happened. I just didn’t feel much for the story.