Set among an affluent Manhattan family, the narrative follows the emotional collapse of parents Mark (Jeff McCarthy) and Susan (Kate Burton) alongside their surviving children following the suicide of their eldest daughter, Samantha (Betsey Brown). As the parents drown their grief in alcohol, neglect, and extramarital escapades, their teenage children, Joshua (Peter Vack) and Amanda (Troian Bellisario), are left isolated. Bound by shared trauma and neglect, Joshua and Amanda develop an unhealthy, co-dependent bond. Under the influence of drugs and grief, their intense sibling attachment crosses physical and emotional boundaries before they are forced to confront the destructive nature of their family dynamic.