Thin Air is the next book in Ann Cleeves' Shetland series - which is now a major BBC One drama starring Douglas Henshall as detective Jimmy Perez.
A group of old university friends are on holiday in Unst, Shetland's most northerly island, to celebrate the wedding of one of their friends to a Shetlander. But late on the night of the wedding party one of them, Eleanor, disappears - apparently into thin air. It's mid-summer, a time of light nights and unexpected mists. The next day Eleanor's best friend Polly receives an email from her saying she'll never be found alive. And so it seems, because the woman's body is found, lying in a small loch close to the cliff edge.
Before she disappeared Eleanor claimed to have seen the ghost of Peerie Lizzie, a child who was drowned close by in the 1920s. As Detectives Jimmy Perez and Willow Reeves investigate, they, too, begin to feel that there is more to the story than meets the eye . . .