Plot
Lara Jean Song-Covey, accompanied by her sisters, Kitty and Margot; her father, Dan; and her neighbor and father's girlfriend Trina Rothschild, visits Seoul for spring break. She reconnects with the memory of her mother by searching for a lock her mother had left on a bridge to memorialize her love for Dan, and finally manages to read her accompanying message, which says "for the rest of my life."
Returning home, Lara Jean mentions to her boyfriend, Peter Kavinsky, that the two of them never had a meet-cute, meeting Peter's disbelief because he remembers their first meeting quite well. They don't have a song either, so he starts brainstorming songs. She nervously waits for the result of her Stanford University application so she can attend college with Peter. She has also applied to the University of California, Berkeley and New York University as safety schools.
Dan proposes to Trina, and as the family begins to plan their upcoming wedding, they decide the three sisters will be the bridesmaids. Lara Jean is disappointed when she is rejected by Stanford. A dream she's had of her future with Peter seems to vanish.
A wrongly sent text to Peter makes him believe that Lara Jean got in, so he shows up in full Stanford regalia, overjoyed. Then he whisks her off to their favorite diner to celebrate. Lara Jean keeps trying to tell him, but he interrupts with a promposal. The next day, wanting to avoid telling Peter she plans to play hooky from school, when she gets an acceptance letter from Berkeley.
On their senior trip to New York City, Lara Jean finally tells Peter about the mix up. Peter takes the news well, and the two remain confident that they can make their relationship work since Berkeley is only around an hour away from Stanford by car. The next day, Lara Jean and her friend Chris get invited to a NYU party which she enjoys immensely, finding herself drawn to the city and the university's program.
Back home, on a date night with Lara Jean, Peter's formerly absentee father reaches out to him, proposing they try to reconnect over a meal despite the years of his absence. Shortly thereafter, she discovers that she has also gotten into NYU. Lara Jean is torn between going there and the plan she and Peter had made, but she ultimately chooses to go to NYU.
Peter's disappointment at her decision is palpable. Although the evening of prom initially starts out well, Lara Jean cannot shake a feeling of impending doom. She invites him up to her room afterwards, planning to finally lose her virginity. She also gives him a box of their mementos before. Believing Lara Jean's farewell gestures to be a sign of them growing apart, Peter breaks up with her to save himself from what he sees as the inevitable breakdown of a long-distance relationship.
Respecting Lara Jean's wishes, Peter skips Dan and Trina's wedding. Instead, he meets up with his estranged father over coffee. His father apologizes to Peter for his absence, saying that one should do whatever it takes for the person they love, causing Peter to realize that he should be doing the same for Lara Jean. After the wedding festivities, Kitty conspires with Peter to set up a meeting between him and Lara Jean under the wedding tent. She finds a letter in her yearbook from him containing his account of their first meeting in sixth grade and a proposed contract to always love each other despite the 3,000 miles (4,800 km) between Stanford and NYU. Peter walks in and asks Lara Jean to sign it, to which she joyfully assents. They dance to a song Lara Jean had heard at the NYU party, with Peter agreeing that it is indeed their song.
The film ends with Lara Jean's reflection on wanting what she has with Peter, regardless of what films say and what stereotypes say about long-distance relationships. She remains optimistic that the distance will offer them the opportunity to keep writing love letters to one another.
