I Know What You Did Last Summer by Lois Duncan

First published: 1973

Subjects: Crime, emotions, friendship, social issues, and war

Type of work: Novel

Type of plot: Moral tale and mystery

Time of work: The early 1970’s

Recommended Ages: 13-18

Locale: Albuquerque, New Mexico

Principal Characters:

  • Julie James, a high school senior and the backseat passenger in a car involved in the hit-and-run accident
  • Barry Cox, the driver of the hit-and-run vehicle, who swears his three passengers to secrecy
  • Helen Rivers, Barry’s girlfriend, a self-centered television weather girl who is in the front seat of the car
  • Ray Bronson, Julie’s former boyfriend and the other backseat passenger in the car
  • Bud, a Vietnam War veteran who currently dates Julie
  • Collie, a young man whom Helen meets at her apartment complex

Form and Content

I Know What You Did Last Summer is a somber examination of responsibility and the effects of the Vietnam War on the youth who served in it. Narrative and dialogue are sober in style as each of the four teenagers involved in a hit-and-run accident searches his or her own conscience, examines the effects of the incident on other factors in their lives, and painfully learns the results of group actions. Tension and suspense build to a plot twist and the revelation of the avenger’s identity. Red herrings and suspicious characters keep readers guessing, although clues to the avenger’s motive and identity are planted throughout the skillfully crafted plot.

Lois Duncan hooks her readers on the first page with a suspenseful opening paragraph that hints of events to follow: “The note was there, lying beside her plate when she came down to breakfast. Later, when she thought back, she would remember it. Small. Plain. Her name and address hand-lettered in stark black print across the front of the envelope.” The seriousness of the matter and the setting are established at the outset. The author sets a troubled mood, provides basic information about characters and place in the story, and reveals something about Julie in particular and other characters in general. The plot contains two levels: the personal problem that the main characters must handle and the mystery that must also be solved.

This blend of morality and mystery features believable characters with whom the reader can identify. The teenagers involved may not always be admirable, but they are realistic. The story is told primarily from Julie’s perspective. A year has elapsed since the four teenagers driving much too fast hit a young boy on a bicycle and left the scene. Barry convinced his passengers that it would do no good to report the crime. In his words, “Taking the blame won’t bring him back. No one will ever know who did it.” Although Ray had second thoughts and later reported the accident, it was too late; the boy was dead.

The four have gone their separate ways over the year since the accident, and, as the story opens, Julie finds two envelopes waiting at the breakfast table. The first is a much-anticipated college letter of acceptance, and the second is an anonymous note containing the message “I know what you did last summer.” Julie’s letter is soon followed by a series of threatening notes and telephone calls to the other three. A few nights later, Barry is lured to the college football field by a mysterious telephone call. He is shot and ends up paralyzed. Helen is also attacked, and she, Julie, and Ray begin to fear that the attacker is bent on killing them all.

In an effort to defend themselves, Julie and Ray join forces to discover the identity of the avenger. They go to the home of the boy who was killed and find only a girl not much older than Julie. She informs the pair that she is the boy’s half sister and that her mother is in another town because of a breakdown suffered after the accident.

The story reaches its climax on an evening when Julie and Helen are both attacked by a young man whom Julie has dated as “Bud” and whom Helen has met as “Collie” in her apartment complex. Both are saved, and Julie and Ray realize that they can never erase or undo the accident but that they can face it. The ending of the novel is far from optimistic.

Critical Context

Lois Duncan’s place in young adult literature is assured. Her books are popular with teenagers and valued increasingly by teachers and librarians. Books dealing with the theme of personal integrity are useful vehicles for classroom discussion. I Know What You Did Last Summer is a realistic novel laced with tragedy and one that provides no happy ending for all of its protagonists, which is a departure from traditional upbeat endings for young adult mysteries. Duncan’s work following this novel confirms her mastery of the suspense/mystery novel and her continuing interest in responsibility and group loyalty. In Killing Mr. Griffin (1978), another blend of morality and mystery, a group of teenagers are involved in a situation that turns unintentionally deadly. The selfishness of two of the group’s members leads them all into lives of guilt and lies. Susan is easily swayed when Mark decides to kidnap their English teacher. The teenagers are in the process of performing this act when the teacher has a heart attack and dies.

In 1992, Duncan became the fourth recipient of the Margaret Edwards Award. Sponsored by the American Library Association, the award recognizes writers whose books have given young adults a window that will help them understand themselves and their role in society. The books singled out by the award committee include both I Know What You Did Last Summer and Killing Mr. Griffin. The award committee cited Duncan’s diverse world of individuals: the fortunate, the underprivileged, the weak, the strong, the good, the evil, the impatient, and the submissive.

Duncan’s work has been praised by her readers, reviewers, and peers. A number of her novels have been honored by the Mystery Writers of America, The New York Times, and the American Library Association. All feature characters who struggle with truth and courage to reach maturity.