1920, rural Ireland. Anglo-Irish twins Rachel and Edward share a strange existence in their crumbling family estate. Each night, the property becomes the domain of a sinister presence (The Lodgers) which enforces three rules upon the twins: they must be in bed by midnight; they may not permit an outsider past the threshold; and if one attempts to escape, the life of the other is placed in jeopardy. When troubled war veteran Sean returns to the nearby village, he is immediately drawn to the mysterious Rachel, who in turn begins to break the rules set out by The Lodgers. The consequences pull Rachel into a deadly confrontation with her brother - and with the curse that haunts them.

Rachel, une agent de police récemment transférée dans un village de campagne, arrête le seul criminel du coin lors de sa première tournée de nuit. Si elle l’arrête facilement, elle ne tarde pas à découvrir que sa présence au commissariat fait remonter à la surface le passé trouble de la petite communauté. Et ces réminiscences prennent des formes diverses : massacre d’une famille entière, crime homophobe...