Guest Stars Steven Robertson as DC Sandy Wilson Alison O'Donnell as DS 'Tosh' MacIntosh Lewis Howden as Sgt Billy McCabe Mark Bonnar as Duncan Hunter Erin Armstrong as Cassie Perez Finn Den Hertog as Drew Alison Peebles as Vicky Kirkland Gemma Chan as Hattie James Sophie Rundle as Sophie Lindy Whiteford as Jackie Haldane Geraldine Alexander as Gwen James Claire Rafferty as Anna Haldane Jim Sturgeon as Ronald Haldane Martin Wenner as Professor Paul Berglund Alexander Morton as Joseph Wilson James Greene as Andrew Haldane