Okay, this was not what I expected. I don't want to say too much, but the characters are sympathetic and believable. The plot hangs on an unexpected quirk of nature, and hangs together. It's good, very readable, and technically I saw no flaws.
The dialogue is realistic (one of my current pet peeves is stilted dialogue).
There's no graphic sex, only a brief lesbian encounter that slides past with barely a ripple, except for a lingering aftermath in relationships.
The only disappointment for me was that I didn't want it to end where it did. I wanted more. But I liked what I got.