Successful cellist Matilda Grey puts her career on hold to investigate whether her mother's suicide is connected to the disappearance of a girl from a Welsh village.

Matilda has unsettling encounters with residents of Penllynith and grows increasingly suspicious of Rose, while events in Dean House become evermore sinister.

Matilda's revelation reopens old wounds for the residents of Penllynith, and the Dean family's sinister connections are revealed. Rose is pushed to breaking point.

Matilda starts to piece things together, with help from an unexpected source. Graves investigates the suspicious circumstances surrounding Ewan's death.

Laura warns Matilda that she is in grave danger, as Graves grows suspicious of Aron and Ed, and Hal vows to get to the bottom of things once and for all.

Matilda ignores Sean's advice that she should leave Penllynith, choosing instead to protect Davey.