After reading Sutherland's book for the first time, Reinhart knew she had to adapt it. "It just made my heart feel full," she says. "The director, Rich Tanne, and I met in Vancouver when I was filming Riverdale and we talked about our vision for what the movie should be, and we were really on the same page and thought the same way tonally in what we saw for this movie."

Tanne was also surprised by how strong an urge he had to tackle the story after reading the book. "It really appealed to me because unlike most teen romance movies, it wasn't a story about the first great love of your life, it was a story about the first great heartbreak of your life," he says. "I could really relate to that. It wasn't until after I finished writing the script that it dawned on me how closely my own high school heartbreak mirrored that of Grace and Henry's story."