Some of the reviews on Goodreads suggest that the prologue gives too much away. I completely disagree. I could hardly bear to read the tense, climactic encounter between Liz and Mary — I was becalmed 50 pages from the end for three days. If I hadn‘t known what Helen didn‘t know, I‘d never have been able to finish. Also, I don‘t think I‘d have enjoyed the book as much without knowing what the prologue implies about Helen.