It's midsummer in Shetland, the time of the white nights, when birds sing at midnight and the sun never sets.

Artist Bella Sinclair throws a party to launch an exhibition of her work and to introduce the paintings of Fran Hunter. The Herring House, the gallery where the exhibition is held, is on the beach at Biddista, in the remote north west of the island. When a mysterious Englishman bursts into tears and claims not to know who he is or where he's come from, the evening ends in farce.

The following day the Englishman is found hanging from a rafter in a boathouse on the jetty, a clown's mask on his face. Detective Jimmy Perez is convinced that this is a local murder. He is reinforced in this belief when Roddy, Bella's musician nephew is murdered too. But the detective's relationship with Fran Hunter clouds his judgement. And this is a crazy time of the year when night blurs into day and nothing is quite as it seems.