In Liane Moriarty's Big Little Lies, the storyline follows the lives of three women who become friends through a meeting at their kindergarten-aged children's school orientation. The women— Jane, Madeline, and Celeste—are brought together through their children but soon form close bonds in which they support each other through the traumas they have faced and continue to face. Jane, a single mom, was raped at the age of nineteen; that is how she conceived her son, Ziggy. Jane is worried about her son, as he is being accused of bullying a classmate. Madeline fears that her daughter will form a stronger bond with her step mother, Bonnie, than Madeline. Celeste is being physically abused by her husband, Perry. As the women grow closer, they share their struggles with each other. When Jane shares that she was raped by a man named Saxon Banks, Celeste and Madeline realize that Perry says he has a cousin named Saxon Banks, and they decide to not inform Jane because they do not want to further traumatize her.

All the while, Celeste is continuing to be abused by her husband who is escalating his violence against her. In order to protect herself, Celeste secretly rents an apartment where she can escape his abuse. After Jane's son, Ziggy, is accused again of bullying his classmate, Jane speaks with her son and learns that, in fact, one of Celeste's twin boys is the bully. Jane confronts Celeste about this, and Celeste realizes that her boys are picking up abusive behavior from Perry. She knows that she must try to further separate herself and her children from him. In the midst of all these heavy situations, the women provide a sense of comfort and humor for each other. Readers are able to enjoy this humor as they navigate the serious and frightening aspects of the novel.

The story climaxes as the women attend a school function, in which Jane recognizes Perry as "Saxon Banks". When she confronts him as the man who raped her, Perry acknowledges that he did violate her and shows no remorse for his act. When Celeste confronts Perry, he begins hitting her, and Bonnie protects Celeste by pushing Perry off a balcony. Perry is killed by the fall, and the women vow to protect Bonnie. However, Bonnie decides to report herself to the police and ends up receiving no jail time. As the novel comes to a close, Celeste begins a speaking tour wherein she speaks about her experience enduring domestic violence.