The following version of this book was used to create the guide: Taddeo, Lisa. Animal. Avid Reader Press, 2021.

Lisa Taddeo's novel Animal is written from the main character Joan's first person point of view. The novel employs an unconventional narrative structure and uses both the past and present tenses. The following summary uses the present tense and a largely linear mode of explanation.

After Joan's married lover, Vic, kills himself in front of her at a restaurant, Joan flees New York City. She decides to move to Los Angeles, California because this is where her half sister, Alice, lives. Though she has never met Alice, Joan believes she is the only person she has left in the world.

Joan moves into an unkempt house on a communal property in Topanga Canyon. One of her neighbors, Lenny, is an elderly man who recently lost his wife, Lenore. Joan immediately dislikes Lenny as he is brusque and brutish. Another of her neighbors is a young man named River. Joan is immediately taken with River. After a night of drinking, Joan and River have sex.

Not long later, Joan starts working at a local health food store café. While here she meets Alice, who comes in for a bowl of soup. The two sit together, drinking beers and exchanging stories about their dating experiences. Alice listens to and comments on Joan's stories, seemingly enthralled with Joan's New York life. For the first time in years, Joan feels seen and validated by another woman. Over the following weeks, she becomes increasingly desperate to be close to and loved by Alice.

Joan begins receiving text messages from Vic's wife, Mary. Mary informs Joan that her daughter, Eleanor, is on her way to California to kill Joan. Joan doubts this is true, but not longer later, Eleanor appears on her doorstep with a gun. Joan begs her not to kill her, lying and saying she is pregnant. She is shocked when Eleanor forces her to take a test and the test reads positive. The baby's father is a man who raped Joan on her trip out West.

Eleanor's prolonged stay with Joan disrupts Joan and Alice's friendship. Alice feels that Joan is being too nice to Eleanor, and that she should kick her out. Joan is afraid to hurt Eleanor, who has become unexpectedly attached to her. She realizes that Eleanor is not so different from herself.

When Joan was just 10 years old, her mother, Mariapia, discovered that her husband, Mimi, was cheating on her. Mimi told Mariapia that his lover was pregnant and that he planned on leaving her and Joan for his alternate family. Furious that Mimi could not love her or Joan enough, Mariapia stabbed Mimi to death and then killed herself. Joan found their bodies, an image that has haunted her for decades.

June starts bleeding and experiencing excruciating pain. She soon births her fetal son. He stays alive for a few minutes in her hand. She feels love and peace she has never felt before. Then the baby dies and her happiness turns to rage.

When Lenny comes over afterwards, he falls into an episode and Joan pretends to be his late wife Lenore. She lures him into the bedroom and strangles him to death. The act is a response to her son's death, her parents' deaths, and Lenny's string of lascivious acts.

Joan moves out of the Canyon and sends Eleanor home. She steals and sells Lenny's old watch for money. Then one day she returns to the Canyon to collect her couch. While there, she sleeps with River.

Several months later, Joan goes into labor unexpectedly. Though she and Alice have had a falling out, Joan calls her as she has no one else. On the way to the hospital, Joan tells Alice they are sisters and how her parents died.

Joan has a difficult labor. After giving birth, the doctors let her hold her daughter for five minutes. Knowing that she will most likely die from childbirth complications, Joan is desperate to tell her daughter everything before it is too late.