There's been a murder!
Cass Lynch, liveaboard skipper and amateur sleuth is busy at the marine college in Scalloway until, one night, she finds an acquaintance dead in a doorway. The victim's hand is smeared with peat ash.
Rumours spread of a strange ritual linked to the witches once burned in Shetland's ancient capital, of horned figures abroad in the night, and the townsfolk are behaving strangely...
...and then there is another murder.