Ghosts of the Vikings

"Treasure hunters and opera stars collide in the north of Shetland in this latest of the Cass Lynch mysteries. Cass has embarked on a tentative relationship with DI Gavin Macrae and they are both invited to the gala opening of her mother's new opera. The performance goes well but it is soon clear that things are not as smooth backstage. As the wind rises, and the power goes off, even Cass's much-loved yacht Khalida can't provide a refuge from a ruthless killer"--Publisher's description.