The story follows the lives of a 14 year old boy named Jack and his three siblings: 17 year old Julie, 13 year old Sue, and 6 year old Tom. The novel begins with the death of their father, an event is soon followed by the death of their mother. Not wanting to be taken into foster care, the children bury their mother in the cellar, covered in cement, and attempt to survive without any adult supervision.
As time passes without adult supervision, Jack and Julie attempt to fill in the shoes left empty by their mother and father. Meanwhile, Jack begins to develop an incestuous crush on his older sister but does not act on it. Tensions heighten when Julie begins to date Derek, a 23 year old man, and Jack openly antagonizes Derek. However, the children had not properly sealed their mother's body in cement and it quickly begins to decompose, creating a fetid stench. Derek finds something amiss, and becomes increasingly interested in the cellar of the house. Jack manages to temporarily defuse the situation and sate Derek's interest by telling him that the body of the family's dead dog was buried in cement in the cellar.
Jack soon finds out that Derek suspects that the children's mother is in the cellar and doesn't know what to do. He heads into Julie's room naked, but she isn't around and only Tom is lying in his crib. Soon after Jack talks Tom to sleep, Julie enters but is unfazed by Jack's nakedness. She then undresses and things get heated between them. Just as they are about to engage in intercourse, Derek enters the room and denounces all of their actions are "sick". He leaves, and the brother and sister begin to have sex. From the room, Derek can be heard breaking open the cement shell in which their mother was trapped. The novel ends with the children reminiscing about their mother as the police approach their house.
