Ægir had become fired up by the idea; this might be their only chance to sail the ocean in a luxury yacht, and the voyage would also solve a specific problem that had been troubling him. [loc. 373]
A repossessed luxury yacht crashes into the harbour wall at Reykjavik. It turns out that there's nobody on board at all. So what has happened to the crew of three, and to the family of four -- banker Ægir, his wife Lára, and their twin four-year-old daughters Arna and Bylgja -- who have sailed from Lisbon to Iceland? Thora Gudmundsdottir, engaged by Ægir's parents, is determined to find out: not just because it's an intriguing case, but because she wants to secure the future of the third daughter, Sigga Dögg.
It's a classic locked-room mystery and Sigurdardottir unravels it in two parallel strands: the events on board the yacht, and the investigations of Thora and her team in Iceland. Is the yacht cursed, as some believe? Is there some supernatural force at work? Why did nobody radio for help? And where are the missing persons?
The mystery unravels slowly and in a generally satisfactory way (though I have to say I found Ægir, in particular, annoyingly stupid). I was less interested in Thora and her domestic, social and professional relationships: perhaps if I'd read other novels in the series I'd be keener to see how these evolved.