Karen M. McManus is the New York Times bestselling author of One of Us Is Lying, Two Can Keep a Secret, and One of Us Is Next. Known for her fast-paced, suspenseful murder mysteries that center around the lives of teenagers, McManus utilizes flashbacks and multiple first-person narrators to spin a complex narrative of greed, revenge, and shocking family secrets. Set on a small, fictional island off the coast of New England, The Cousins takes place in the present day with flashbacks to 1996 and offers a peek into the dark secrets of a wealthy and well-established family. The version used for this guide is the ebook of the Delacorte Press imprint by Random House Children’s Books.

Plot Summary

The Cousins is an account of the wealthy Story family and the mystery that drove them apart 24 years ago. Mildred Story was married to Abraham Story and lived with him on Gull Cove Island with their four children: Adam, Anders, Allison, and Archer. Shortly after Abraham passed away, Mildred mysteriously disowned and refused to see her college-aged children. Mildred offered no explanation for her abrupt disconnection from her children other than a cryptic one-sentence letter sent by her lawyer: You know what you did.

Twenty-four years later, in the present day, three of Mildred’s children have children of their own. Milly is the daughter of Allison, Aubrey is the daughter of Adam, and Jonah (or JT) is the son of Anders. Out of the blue, the grandchildren receive a bizarre invitation from their grandmother to spend their summer at Gull Cove Island, and at the insistence of their parents, they agree. However, the grandchildren quickly realize that their grandmother wasn’t the one who invited them. She appears to be shocked to see them, and her lawyer is eager to remove them from the island.

Jonah is revealed to be an imposter sent by the real JT, who didn’t want to waste his summer on Gull Cove Island. Jonah is on a mission to get revenge after Anders Story swindled his family and left them bankrupt, and he plans to ensure that Anders never has the chance to inherit money. Milly and Aubrey both have strained relationships with their parents, and their Uncle Archer—who has been hiding out on Gull Cove Island—has alcoholism. Everyone in the Story family seems to harbor some degree of trauma from the fallout 24 years ago.

Through a series of flashbacks, the reader learns that Allison became pregnant in the summer of 1996 after a one-night stand with a local boy named Matt Ryan. However, Matt didn’t want a relationship with Allison, and he chose Anders’s ex-girlfriend, Kayla. Allison had a miscarriage, but Adam and Anders decided that Matt needed to be punished for disgracing their family name. Anders convinced a drunk Matt that Kayla fell into the water at a beach party, and Matt jumped in to rescue her. He drowned, and Allison helped cover up his death.

The Story grandchildren discover that the woman masquerading as Mildred is actually Theresa Ryan, Mildred’s old assistant and the mother of Matt. The real Mildred died 24 years ago, and with the help of Donald Camden, Theresa took her place, became a recluse, and disowned Mildred’s children so no one would catch her in the act. However, Aubrey notices that “Mildred” doesn’t have her signature birthmark on her hand, and the truth comes out. Theresa wanted to punish the Story children for their involvement in her son’s death. She sets the Story family house on fire and dies from smoke inhalation, while Aubrey and Archer barely manage to escape. The surviving members of the Story family learn that Theresa and Donald used up all of the money in the Story family estate, and the family is left with nothing.

In the end, Milly starts to connect with her mother, and Aubrey finds a father figure in her Uncle Archer. The Story family begins to grieve the death of Mildred and move on with their lives, and Jonah, Milly, and Aubrey become inseparable. The family begins to understand the power of forgiveness and how a need for revenge can destroy lives. Jonah receives a letter from Theresa’s accomplice who helped set the fire, and she warns him to keep his parents away from Anders.