Martha Johnson wants to be a good mother and a devoted wife. It’s all she’s ever wanted in life, and she tries her very best, but when her husband threatens to leave her, her desperation reveals only one strategy that can save her family, punish her ungrateful husband, and earn power: murder.

Over a five-year period, Martha Johnson murders her four children, one by one, in order to punish her husband when they argue, but Martha is no ordinary serial killer. She murders her children by using the bulk of her 250-pound body to suffocate them. Unlike other fictionalized true-crime novels, Underneath neither valorizes nor focuses on the specific acts of violence. Instead, it attempts to understand how feelings of powerlessness, the residue of trauma, and the need to find justice in a world that refuses to give a fat body justice finds its only respite through murder.