I Know What You Did Last Summer

by Lois Duncan

Start Free Trial


Download PDF PDF Page Citation Cite Share Link Share

Author: Lois Duncan (b. 1934)

First Published: 1973

Type of Work: Novel

Type of Plot: Thriller

Time of Plot: 1970s

Locales: Unnamed town in the U.S.

Principal Characters

Julie James: high school senior planning to attend Smith College in the fall; she is the first to receive the threatening letter reading “I Know What You Did Last Summer”

Helen Rivers: former classmate of Julie's who dropped out of high school to become a local weather forecaster

Ray Bronson: Julie's former boyfriend who left town after high school graduation to hitchhike up the California coast

Barry Cox: Helen's boyfriend who graduated high school with Ray and attends the local university

The Story

After working to bury the memory of a tragedy in which she played a role, seventeen-year-old Julie James receives an anonymous letter reading, simply, “I Know What You Did Last Summer,” and is forced to confront her past. One year earlier, after celebrating at a high school graduation party for her boyfriend Ray and his best friend, Barry, Julie and Helen, Barry's girlfriend, Barry, and Ray are involved in a car accident. Barry, who is driving Ray's car, accidentally hits and kills a young boy on a bicycle. Fearing criminal prosecution, especially as they had all been drinking and smoking pot at the party, the four friends flee the scene and vow to never speak of the event again.

Following the accident, the four friends go separate ways: Julie breaks up with Ray, withdraws socially, and focuses on her studies; Helen drops out of school to take a job as a local weathergirl; Ray departs for California, where he plans to hitchhike up and down the coast; and Barry attends college and continues to date Helen casually. After Julie receives the anonymous note, she contacts Helen, who calls Barry, and the three agree that it must be a prank. Soon after, however, the friends revise their theory when Ray returns to town and receives a newspaper clipping describing the accident in the mail and Helen finds a picture of a boy on a bicycle taped to the door of her apartment.

After Barry is shot following a mysterious telephone call arranging a meeting with the friends' anonymous pen pal, Julie and Ray work together to determine who is stalking them. The two feign car trouble to visit the home of the boy they had killed and discover that the boy's death had led to his mother's nervous breakdown and hospitalization. After a conversation with the boy's sister, Ray and Julie determine that their stalker is not a member of the boy's family. They then consider Helen's sister Elsa, as she has always been jealous of Helen.

The friends' stalker ultimately unmasks himself, and is revealed to be a person who has recently insinuated himself into their lives. After an attempt on both Helen's life and Julie's life, the letter-writer is exposed and the truth about the past comes to light.

Critical Evaluation

Lois Duncan's writing for young adults falls firmly within the suspense thriller genre and I Know What You Did Last Summer is no exception. Published after early thrillers Ransom (1966) and They Never Came Home (1969) and right before her later and more supernaturally tinged novels of suspense Down a Dark Hall (1974) and Summer of Fear (1976), I Know What You Did Last Summer addresses, as Duncan's other YA novels do, two themes Duncan has asserted are present in all of her works for teens: “the importance of resisting peer pressure and taking responsibility for your actions” (Kaywell).

Duncan's young adult thrillers arguably paved the way...

(This entire section contains 1169 words.)

See This Study Guide Now

Start your 48-hour free trial to unlock this study guide. You'll also get access to more than 30,000 additional guides and more than 350,000 Homework Help questions answered by our experts.

Get 48 Hours Free Access

for R.L. Stine's “Fear Street” series and Christopher Pike's stand-alone horror novels, works that achieved significant popularity in the 1990s. Like Stine's and Pike's books, Duncan's novels feature “protagonists [who] are high school students—usually young women—who find themselves suddenly confronted with a sinister threat to their ‘normal’ existence” (“Duncan, Lois”). This characteristic, as well as some of the “core elements” librarian and critic Patrick Jones associates with the YA thrillers of the 90s—the appearance or suggestion of the supernatural and the threat to expose a secret—are certainly present inI Know What You Did Last Summer. In fact, Pike's 1986 novel, Chain Letter, features a premise strikingly similar to that of I Know What You Did Last Summer.

Reviews of I Know What You Did Last Summer note the chilling effectiveness of Duncan's novel. While the threatening notes and the mystery they create are at the center of the story and provide the most obvious “scares,” Duncan's book, like many of her other thrillers, brings the themes of “trust, loyalty, and betrayal” common in the YA thriller genre to the fore (Campbell). The novel also offers commentary specific to the period in which it was written. As it introduces a character who has recently returned from fighting in the Vietnam War, the novel “suggest[s] … the long term effects of the Vietnam involvement on a generation of American young.” (Churchill).

I Know What You Did Last Summer was made into a movie starring Jennifer Love Hewitt (as Julie) and Sarah Michelle Gellar (as Helen) in 1997. Duncan had little involvement with the creation of the movie and expressed dissatisfaction with the production. As she told Joan Kaywell in an interview published in the Journal of Adolescent and Adult Literacy: “I was kept so far out of the loop that I had no idea what was being done. Once I saw the movie, I understood why.”

In 2010, Duncan's publisher announced plans to publish a new edition of I Know What You Did Last Summer as well as other YA titles from her backlist. The revised version of I Know What You Did Last Summer features new cover art, an interview with the author, and updated text. In an interview with Publishers Weekly, Duncan explained that she found surprisingly little of her original text needed revision; “just little fringe things … had to be reworked, mostly due to today's technology,” she said (Lodge). She added technological accessories, updated descriptions of her characters' wardrobes, and modernized dialogue, maintaining the core and essence of each novel while re-situating her stories in a more contemporary milieu.

Further Reading

  • Duncan, Lois. Lois Duncan. Web. <http://loisduncan.arquettes.com/>
  • Stelloh, Tim. “Who Killed Lois Duncan's Daughter?” BuzzFeed News. BuzzFeed, Inc., 30 May 2014. Web. 27 February 2016.


  • Campbell, Patty. “The Sand in the Oyster.” Horn Book 70.2 (March/April 1994): 234 – 240. Library and Information Science Source. Web. 27 February 2016.
  • Churchill, David. Rev. of I Know What You Did Last Summer. The School Librarian 30.1 (June 1982): 151-152. In Children's Literature Review. Ed. Gerard J. Senick. Vol. 29. Detroit: Gale, 1993. Children's Literature Review Online. Web. 26 February 2016.
  • “Duncan, Lois (1934-).” Major 21st-Century Writers. Ed. Tracey Matthews and Tracey Watson. Vol. 2. Detroit: Gale, 2005. Gale Virtual Reference Library. Web. 27 February 2016.
  • Jones, Patrick. “Nothing to Fear.” Collection Management 25.4 (2001): 3 – 23.
  • Kaywell, Joan. “An Interview with Lois Duncan.” Journal of Adolescent and Adult Literacy 56.2 (March 2009): 545. Literature Resource Center. Web. 26 February 2016.
  • Lodge, Sally. “Lois Duncan Thrillers Get an Update.” Publishers Weekly. PWxyc, LLC., 23 September 2010. Web. 26 February 2016.

Critical Essays