The revelation of Stanley and Anatole's true intentions puts the Hawkins family in danger. With Mia speaking at the commission, Laura must do everything in her power to stop an awful attack. Leo and Mattie return to the Elster house where Leo comes to understand a painful truth - but Mattie has a secret that could knock their fledging relationship off course. Niska continues her mysterious journey to Wales, where she must defy all her instincts to survive. Sci-fi drama, starring Katherine Parkinson, Colin Morgan, Lucy Carless, Emily Berrington and Gemma Chan.