A survey vessel trawls up a man's body in the Outer Hebrides and ship's engineer Helen finds a compelling green stone in his pocket. On Rannoch Moor, her cousin Malcolm, a local ranger, is visited by a strange woman. She goes missing, and he too finds a green stone. The cousins have stumbled upon a multi-faceted conspiracy involving the high-tech company Fundamantal Forces who are promising limitless green energy from under the moor. It's soon clear that deeper, perhaps darker forces are at play. Helen and Malcolm have twelve days to learn to cooperate, piece the mystery together, and save the multiverse.

Equinox brings together procedural thriller, Scottish myth, many-worlds science and family drama. Set in the present-day Scottish Highlands and Islands it has the verve and imagination of Ben Aaronovitch's Rivers of London, melding themes of trust, loyalty and memory.