Among her possessions, Matilda discovers tantalising evidence, linking her mother to the Welsh girl's disappearance all those years ago. And so grief stricken Matilda travels to Wales, determined to find out who she really is, even if it means unraveling her own identity. In the process, she uncovers long buried secrets in this remote community - including one secret more bizarre, terrifying and dangerous than anything she could have imagined: Dark otherworldly forces are gathering - they have been waiting many years for Matilda to return.
It's a thriller-cum-horror, although the thriller bits feel a bit well-trodden and the horror bits, so far, are mainly confined to persons unseen making "oo-wah-oo-wah" noises while various characters freak out at mirrors.
It prefers to take its time and lets the narrative play out at its own pace rather than going for cheap shock tactics, though the big revelation that closes the first episode is a genuine gasp-out-loud moment.
It is scary. It might have been scarier still if there were a little more sotto voce between the full-on fortissimo Hammer horror, for the imagination to get to work.