Jack
A 14 year old boy who has an incestuous crush on his older sister Julie. He attempts but is unsuccessful at filling the shoes of his late father.
Julie
A 17 year old girl who attempts to take over the role of the motherly figure in the house. She later begins to date Derek.
Sue
A 13 year old girl whom we are told that Jack and Julie played doctor with when she was younger.
Tom
The youngest child of the family, Tom is a 6 year old boy from whom Jack finds out of Derek's suspicions.
Derek
A 23 year old young man who begins dating Julie. He later suspects that the fetid stench from the cellar is actually the children's mother. He walks in on Jack and Julie having sex before later breaking open the cement casing holding the children's mother. It is assumed that he is the one who called the police.
The Children's Mother
The children's mother dies very early on in the novel and is buried in cement in the family's cellar.