The One is based on John Marrs’ sci-fi novel of the same name, set in a future where a simple DNA test can find everyone’s perfect partner. As five more couples set to be arranged by science, the story follows what happens when the person you’re meant to be with has dark secrets and even deadlier intentions. The 10-part series will shoot in and around Cardiff, Newport, and Bristol from 14 October and casting director Lauren Evans is attached.