Ann Cleeves is back with Thin Air, the sixth book in her beloved Shetland series, which is now a hit television show starring Douglas Henshall.

A group of old university friends leave the bright lights of London and travel to Shetland to celebrate the marriage of one of their friends. But, one of them, Eleanor, disappears-apparently into thin air. It's mid-summer, a time of light nights and unexpected mists. And then Eleanor's body is discovered lying in a small loch close to the cliff edge.

Detectives Jimmy Perez and Willow Reeves are dispatched to investigate. Before she went missing, Eleanor claimed to have seen the ghost of a local child who drowned in the 1920s. Her interest in the ghost had seemed unhealthy-obsessive, even-to her friends: an indication of a troubled mind. But Jimmy and Willow are convinced that there is more to Eleanor's death than they first thought.

Is there a secret that lies behind the myth? One so shocking that someone would kill-many years later-to protect?