Parental paranoia takes terrifying form in this horror thriller. Sarah (Seána Kerslake) and her young son Chris (James Quinn Markey) are looking at a new phase in their lives when they move to a new home in rural Ireland. Their house is next to a forest, which doesn't seem too ominous — but a large sinkhole opens in a clearing hidden within.

When Chris vanishes one night, Sarah fears that he has ventured into the forest and stumbled into the sinkhole. Then the boy reappears, apparently unharmed — until he begins to exhibit unusual and increasingly disturbing behavior. Is this the same Chris who disappeared, or has he been replaced by some sort of double?