This thing of darkness

A marine engineer who tumbles off a cliff path on a windy night. A burglary where everything taken was returned by the thief. The suicide of a man in love with life. An accident, a mystery, an unexplained tragedy. And nothing at all to connect them. Until, that is, Detective Constable Fiona Griffiths, searching for something - anything - to take her mind off the tedious job of evidence-cataloguing she's been assigned to, starts to wonder if all three incidents are not quite what they seem.