This is what Yrsa does best. Not your fast paced thriller but a slow-burning psychological tale of terror. Not as terrific as her last, which had extra bite because it was based on a true story. Also, I thought there was a glaring error in this but it turned out to be a part of the plot - she made a character able to drive with a broken leg. Still, this character, complete with cast, didn't hide the fact he was driving and no other character questioned it (I guess maybe you can drive an automatic with such an injury). So it had to drop a star.
In this, we are back with Thora and her eternal thorn-in-the-side secretary, Bella. In previous books in this series, I've felt we heard more about domestic whinging than we did a mystery. To so in this - although we keep up-to-date with what her children are doing, home life has been put in the background where it belongs. I even started to thaw towards Bella, who had been made so stupid and sullen in previous books that it became irritating.
This mystery is all the more creepy for being set on a yacht voyage from Lisbon to Reykjavik, with all the superstition of the seafaring community subtly woven in to add to the spine chilling disappearances of those on board. The yacht arrives in port devoid of human life, and the reader is drip fed the circumstances on board and how we lose each person, alternating with Thora and Bella trying to piece together the mystery.
My only further comment must be - buy it and read it.