When the badly decayed body of an elderly woman is unearthed, Detective Chief Inspector Mark Lapslie and his sergeant, Emma Bradbury, are called in on the case. The body provides only two mysterious clues to the identity of the murderer: someone with a deadly knowledge of household plants used shears to clip the fingertips off the corpse's right hand.
But this dearth of evidence is not Lapslie's only problem. He's just returned to the force after a year of relative isolation, trying to avoid the worst symptoms of his synasethsia, a neurological condition that causes him to "taste" sound and that makes his life as complicated as any crime he's been charged with solving.
Now he's flooded again - not only with the convolution of senses that can drive him nearly mad but also with the increasing convolutions of the case. The murder appears to be the work of a serial killer, and the investigation is leading in a direction that could be extremely detrimental to Lapslie's career, if not to his very life.