Can you give me a summary of with My by Lois Duncan?

In Lois Duncan's *I Know What You Did Last Summer*, a group of teenagers, Helen, Bart, Miles, and Sue Ann, are involved in a hit-and-run accident the summer after their high school graduation. They hit a young man, and in a panic, they cover up the crime. A year later, they begin receiving threatening anonymous messages, signed "I know what you did last summer." The messages escalate, leading to terrifying and dangerous situations for each of them. One by one, the teens find themselves in jeopardy as someone seems determined to make them pay for their crime. The novel builds suspense and terror as the friends try to uncover the identity of their tormentor and prevent further tragedy, ultimately revealing a surprising twist concerning the identity of the person who knows their secret. The novel explores themes of guilt, consequences, and the fragility of secrets.