The following version of this book was used to create the guide: Coben, Harlan. I Will Find You. Hachette Book Group, Inc., 2023.

Harlan Coben's novel I Will Find You is written from the first and third person points of view. The novel is a thriller, and primarily traces the protagonist David Burroughs's attempts to relocate his missing son and to prove his own innocence. Although the narrative employs both the past and present tenses, the following guide adheres to the present tense for the sake of clarity. The summary found below abides by a linear narrative structure.

David Burroughs is married to Cheryl, his longtime sweetheart. Although the two have loved each other for many years, when they begin experiencing infertility issues, the couple's bond falters. Desperate for a child of her own, Cheryl agrees to go through with her sister Rachel's plan. Rachel makes Cheryl appointments at a fertility clinic under her name. Although Cheryl accepts the sperm donation, she does not tell David.

When Cheryl gets pregnant with their son Matthew, David believes the treatments that he received improved his sperm count and resulted in his son's conception. He and Cheryl hope that their son will also resolve their marital complications.

One night, when Matthew is three years old, Cheryl is at work and David is babysitting. Frustrated with his life and his marriage, he has a few drinks and passes out after putting Matthew to bed. Some time later, he wakes up and checks on Matthew. He is horrified to discover his son's battered body in his room.

After the neighbor Hilde testifies against David, David is found guilty and sentenced to life in prison. Initially, everyone in David's personal life is skeptical of the sentence. However, seeing the evidence against David, they become unsure what to believe.

Five years into his sentence, Rachel visits David. She shows him a photograph from Six Flags, convinced that the little boy in the background is in fact Matthew. Although he cannot believe it, David sees Matthew too.

The prison warden is David's father's best friend Philip Mackenzie. Not long after, David tells him about the photo and his theory, Philip helps David escape the prison.

David and Rachel work together to find Matthew. They begin by seeking out Hilde. She tells David that she did indeed lie on the stand. She did so in order to protect her own family. From Hilde's home, David travels to his hometown in Revere. Through this journey, he learns that his father may have also tampered with evidence in an attempt to protect his son who he believed was guilty.

As David and Rachel continue working on the case, they uncover new clues and evidence. One day while studying the Six Flags photo, Rachel realizes that Matthew is holding the hand of her former college classmate Hayden Payne. She and David seek him out. They soon discover that Hayden kidnapped Matthew. Convinced that Matthew was his child because of a sperm donation he gave the clinic, Hayden stole him from his bed. He planted the body of an orphan he killed in Matthew's place and pinned the murder on David.

Eight months after David and Rachel uncover the truth, the characters have found redemption and happiness. Cheryl is married to a man named Ronald with whom she has a little girl. David and Rachel have also begun a relationship. Matthew splits his time between the two families.