Trying to escape her broken past, Sarah O’Neill is building a new life on the fringes of a backwood rural town with her young son Chris. A terrifying encounter with a mysterious neighbour shatters her fragile security, throwing Sarah into a spiralling nightmare of paranoia and mistrust, as she tries to uncover if the disturbing changes in her little boy are connected to an ominous sinkhole buried deep in the forest that borders their home. A single mother living in the Irish countryside with her son begins to suspect he may not be her son at all, and fears his increasingly disturbing behavior is linked to a mysterious sinkhole in the forest behind their house.