Netflix's To All the Boys I've Loved Before features part of the plot of Jenny Han's second book, P.S. I Still Love You. In the books, the video leak of Lara Jean and Peter kissing in the hot tub and John Ambrose McClaren's return don't happen until the second novel, which picks up right after the first. But there's still plot to explore in the upcoming movie.
In P.S. I Still Love You, John Ambrose and Lara Jean get in touch again as pen pals after he receives her letter, but he comes back into our beloved protagonist's life in a different way than in the first movie, where he makes just a quick appearance. As the two start getting closer, so do Peter and his ex Gen, so there's definitely trouble in teen paradise.