Guest Stars Alison O'Donnell as DS 'Tosh' MacIntosh Steven Robertson as DC Sandy Wilson 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 Jim Sturgeon as Ronald Haldane Claire Rafferty as Anna Haldane Martin Wenner as Professor Paul Berglund Alexander Morton as Joseph Wilson James Greene as Andrew Haldane