Returning to BBC One Wales on Tuesday 11 February at 9pm and BBC Four on Saturday 15 February at 9pm, the second series will see the return of DCI Cadi John (Sian Reese-Williams) and DS Owen Vaughan (Siôn Alun Davies). When the brutal murder of an ex-teacher is discovered following an anonymous phone call, Cadi leads an investigation in the slate-strewn mountains of Blaenau Ffestiniog. While Cadi and Vaughan have a new case on their hands however, three young friends (Mia - played by Annes Elwy, Connor - played by Steffan Cennydd and Lee - played by Siôn Eifion) have blood on theirs. As their lives - and the investigation - unravels, they soon find out there is nowhere to hide.

Hit crime drama #Hidden continues this year with a six-part second series following the success of the chilling first series.More info and cast interviews: https://t.co/McZWi60gju pic.twitter.com/0aIw5QnpUT

— BBC Press Office (@bbcpress) February 3, 2020

Sian Reese-Williams opened up about the challenges her character is facing when the series returns. "Series two picks up around nine months after series one ends. We find Cadi trying to deal with the grief of losing her father, while trying to keep her head in her work," she explained. "It’s a difficult time for her - just as one begins to come through the initial shock of losing someone and start to try and deal with it, that’s the time that everyone around you starts to forget and move on. She’s also faced with dealing with the estranged daughter of the victim of the case, and the parallels she sees between the two of them are difficult for her to navigate professionally."