In the first series, the cast was as follows: •
Molly Windsor as Emma Hedges, a laboratory technician who has moved back to her birthplace of Dundee, for her new job, and in search of answers about her mother's murder. •
Laura Fraser as Sarah Gordon, professor of Chemistry at the University of Tayside and Emma's new boss at SIFA. •
Jennifer Spence as Kathy Torrence, a professor of forensic anthropology at the University of Tayside and a colleague at SIFA. •
Martin Compston as Daniel MacAfee, director of a construction company and romantic interest of Emma. •
Vincent Regan as Phil MacAfee, Daniel's father and former director of MacAfee Construction. •
Michael Nardone as Detective Inspector Neil McKinven, a friend of Professor Gordon who has insight on the Marie Monroe case. • Phil McKee as Jimmy Levin, husband of Marie Monroe and Emma's stepfather. •
John Gordon Sinclair as Drew Cubbin, Emma's father and ex-partner of Marie Monroe. • Morayo Akandé as Detective Constable Trina Adeboyo, colleague of DI McKinven at Police Scotland. • Jamie Marie Leary as Skye Alessi, Emma's childhood best friend. • Carly Anderson as Marie Monroe, Emma's mother who was murdered in 2001, and whose case remains unsolved. •
Laurie Brett as Izzy Alessi, best friend of Marie Monroe, and mother to Emma's childhood best friend Skye. • Joana Borja as Pia Salvador, forensic scientist and love interest of Professor Torrence. • Andrea Hart as Janine Muir, SIFA's receptionist. •
Anna Leong Brophy as Louise Chiu Jones, chemist and Emma's colleague at SIFA who works alongside her in the lab. •
Neve McIntosh as Julie Hedges, Emma's maternal aunt, who adopted her after the murder of her mother and took her to Manchester. •
Janey Godley as Clare Tindall, a criminal defence lawyer who represents Daniel. ==Episodes==