Landscape artist Josie MacDonald is coming to the end of her stay in Scotland.  Whilst out on a painting trip early one morning she witnesses a horrific murder.

Mr Mac, the deranged killer, is aware that she has seen him at work and sets out to kill her but Josie manages to escape by plunging into the North Sea.

Mr Mac, convinced that she has perished, discovers a few days later that she has survived and sets out to track her down.  He follows her to London where he subjects her to terrible psychological torment as one by one her friends are drawn into the nightmare.

Josie returns to Scotland in order to discover the truth where her worst fears are realised.  With time running out and a killer of the loose she must survive long enough to bring her horrifying ordeal to an end.