16 Biggest Differences Between The Summer I Turned Pretty TV Series and Best-Selling Books (So Far!)

The Summer I Turned Pretty went from page to screen — but not everything stayed the same.

Based on Jenny Han’s best-selling romance trilogy of the same name, the Prime Video adaptation first premiered in June 2021, introducing a new generation of fans to Isabelle “Belly” Conklin (Lola Tung) and the rest of the Cousins Beach crew. The story follows Belly as she spends her summers in Cousins Beach and navigates a complicated love triangle between a pair of brothers, Conrad (Christopher Briney) and Jeremiah Fisher (Gavin Casalegno).

While the Prime Video series follows the same major plot line and re-creates some defining moments from the book (hello, season 3 peach scene!), there have also been some changes along the way. Now in the midst of its third and final season, Han, who serves as showrunner, told Entertainment Weekly in March 2025 that there would be “surprises” — especially for those who are fans of her books.

“There are the things that [fans] know and then there are things they think they know, and then there’s going to be, hopefully, things that surprise them,” she said.

From Susannah’s big secret to a new relationship, here are the biggest differences between The Summer I Turned Pretty book trilogy and the Prime Video show.

Warning: The Summer I Turned Pretty spoilers ahead!

The debutante ball

Remember the drama-filled debutante ball that served as the catalyst for most of season 1’s drama? Well, it never actually happened in the books.

Early on in the TV series, Susannah (Rachel Blanchard) gets Belly an invitation to the ball, which takes place at the Cousins Beach Club. It’s a primary plot point in season 1 as it lays the foundation for Belly’s character arc: While her brother Steven (Sean Kaufman), mother Laurel (Jackie Chung) and Conrad doubt she would participate because they think it isn’t her thing, Belly proves them wrong when she says yes.

At the end of season 1, the debutante ball is the intense culmination of everything that happens throughout the season. After Jeremiah, who is Belly’s escort to the ball, learns of his mother’s big secret, he leaves Belly stranded on the dance floor — that is, until Conrad jumps in to save the day.

In June 2022, Han opened up to TheWrap about the decision to add the debutante ball, saying it was “a chance to really bring a rite of passage like a ceremonial rite of passage of growing up to life.”

“I think different cultures have many different ways of marking that moment of between, like, girlhood and adulthood,” Han said. “And that’s what Deb Ball is, you’re coming out and being seen as an adult.”

Susannah’s cancer secret

Speaking of Susannah’s big secret, it isn’t as under wraps in the book, as both sons seem to be aware of her diagnosis from the beginning.

In the show, however, Susannah insists on keeping her sons in the dark in hopes of having one last normal summer in Cousins Beach — but it’s really only Jeremiah who doesn’t know. Conrad finds out early on, while Jeremiah doesn’t become aware until the season 1 finale, when he takes his mom’s phone and looks through her emails.

Jeremiah’s sexuality

In the show, Jeremiah is more sexually fluid than his book counterpart, and kisses both boys and girls in the first season.

“My approach to this adaptation was: How would I tell the story in 2022? What would that look like? And how would that change things?” Han told TV Line in June 2022 of her decision to add this to Jeremiah’s character arc. “I think perhaps if I was writing the novel today, I may have made that choice because I think that he’s always been a character, to me, that is really at ease with himself, really comfortable in his own skin, and openminded and open to exploration.”

She continued, “I do think that’s more reflective of today and young people today and the way they view sexuality being much more of a spectrum.”

The showrunner acknowledged that, in her eyes, Jeremiah isn’t ready to identify as bisexual, though she considers him “sexually fluid.”

“He is a young person who’s figuring out where he falls in all that and hasn’t experienced a lot of of love yet,” Han said. “It’s still kind of early on in that journey.”

Belly’s kiss and breakup with Cam Cameron

In both the show and book, Belly develops a relationship with someone other than the Fisher brothers: Cam Cameron (David Iacono). But in the show, Cam is her first kiss, whereas in the books, it is Jeremiah.

As for their breakup, in the novel, Cam ends things with Belly because he knows she has her heart set on one of the Fisher brothers. Meanwhile, Belly is the one to call it off in the show.

Laurel’s career

In the show, Belly’s mom, Laurel, is an author, though that was never mentioned in the books. The career choice is an Easter egg that ties the show to the novels, as the book Laurel writes in the second season is titled It’s Not Summer Without You, the name of the second book in Han’s trilogy.

Aunt Julia’s attempt to sell the Cousins Beach house

Season 2 revolves around Susannah’s half-sister, otherwise known as Aunt Julia (Kyra Sedgwick), inheriting the Cousins Beach house and trying to sell it. In fact, it’s what brings Conrad away from Brown University and back to Cousins as he tries to stop the sale from happening.

However, Aunt Julia and her child Skye (Elsie Fisher) don’t exist in the books, and it’s Conrad and Jeremiah’s dad, Adam (Tom Everett Scott), who is instead trying to sell the house.

Conrad’s reaction to Jeremiah and Belly’s kiss in the season 2 finale

Toward the end of the season 2 finale, Belly and Jeremiah share a passionate kiss on the Brown University campus, just as Conrad approaches them. After the intense moment, Belly and the Fisher brothers share an awkward car ride together as Conrad teases them about the kiss from the backseat — though it happened differently in the books.

In It’s Not Summer Without You, Han’s second novel in the trilogy, Conrad completely ignores them the whole car ride after he witnesses Jeremiah and Belly’s kiss.

In August 2023, Han told PEOPLE that the subtle change was a way of demonstrating that Conrad is “still in the fight” for Belly.

“He sees that [infinity] necklace and he’s like, ‘I’m not letting her go. I’m still here.’ Otherwise, he wouldn’t have gotten in the car,” she said. “Even with him being a jerk to both of them, he’s still basically saying, ‘Look at me. Don’t look at him.’ It’s almost like he is still asking for her attention.”

Han continued, “In a way, it’s more active than we’ve seen him be in a while because he can tend to shut down and go within himself throughout his grief.”

Belly doesn’t lose her virginity to Conrad in the books

Belly doesn’t have sex with either Fisher brother in the books, though in the show, she loses her virginity to Conrad in a season 2 flashback, while they’re cuddled up by a fireplace during a getaway to the Cousins Beach house.

In May 2025, Han told Entertainment Weekly that the decision to implement a sex scene was really based on Belly’s character in the show.

“Belly choosing to have sex with Conrad was really driven by Belly and her desire and what she wanted to do,” Han said. “It was really important to me for that moment to be just a very nice memory for her, that is a moment in time where she really loved that person and it happened exactly how she dreamed of and how she wanted it.”

Taylor’s relationship with Steven

Belly’s love triangle isn’t the only intense connection through the series, as some may argue that the chemistry between Steven and Taylor’s (Rain Spencer) is a central part of the show. But in the books, Steven is a much less prominent character — and the peak of his relationship with Taylor is a secret kiss that ends up ruining Belly’s birthday.

In the show, however, the pair’s slow-burn romance picks up in season 2 and culminates with a kiss — and continues into a season 3 on-again, off-again relationship (and a cheating storyline).

In July 2025, Han opened up to TheWrap about why Steven and Taylor’s relationship was one of the “most challenging parts of writing the season.”

“There’s so many places they can go, and we did have that time gap,” she said. “We wrote a lot of story that we never even see on screen, just so that we knew what the history was, and we knew where the fault lines were … in the relationship.”

Steven’s car accident

In the second episode of season 3, Steven gets into a car accident after Taylor insists he pulls over and lets her out during a fight. He survives the car accident, but it leads to the pair’s breakup as he says it serves as a “wake up call” that he shouldn’t be pursuing her anymore. The car accident was entirely new from the book, as Steven didn’t have many of his own storylines in the trilogy.

Taylor’s mom’s financial troubles

Season 3 of the show introduces an entirely new storyline for Taylor’s mom, Lucinda (Kristen Connolly). After breaking up with her boyfriend Scott, Lucinda asks Steven to look at her business’ books, where he discovers she is in serious financial trouble. As a result, Taylor gives up her internship in New York City to stay home and help her mom run the business.

Belly’s knock on Jeremiah’s door

After Belly’s bachelorette festivities in episode 7, she ends up on the beach with Conrad, where he admits he’s still in love with her — and urges her not to marry his brother. After this happened in the books, Belly returned to the house, got in bed with Jeremiah, and said, “I love you,” to his back, per Decider.

However, in the series, an emotional Belly crawls into bed with Taylor instead, where she cries as Taylor Swift’s heartbreaking track, “loml” plays — and knocks on Jeremiah’s wall.

So, why did Belly knock on Jeremiah’s wall? That ritual back to season 1, when the pair would knock on the wall as kids to signal when they’re still awake at night and check on each other. However, now, just days before their wedding, Jeremiah is passed out asleep after getting drunk with his friends, and therefore, Belly is met with silence from the other side of the wall.

Belly’s study abroad destination

In the eighth episode of season 3, Belly and Jeremiah call off their wedding after Conrad’s last-minute love confession. In the aftermath, Belly heads to Paris in hopes of getting her spot back in the study abroad program she was accepted to earlier in the season. The last few episodes follow her fresh chapter in the European city, where she goes on a journey of self-discovery — and tries to escape everything back at home.

Though it’s a small change, Belly instead studies abroad in Spain in the books. Ahead of the finale, Han told Entertainment Weekly that filming the end in Paris was a change she had been planning from the start of the adaptation.

“I mean, the last book is named after Casablanca, so it always felt right. I’ve been putting in Paris Easter eggs since the very beginning of the show too, like how Belly was reading The Hunger Games in French, so I always was planning this,” she said. “I just always loved the idea of a girl going to find herself in Paris and fall in love, it’s just so much more romantic.”

Conrad and Jeremiah’s heart-to-heart at their mother’s grave

In the second-to-last episode of the series, Belly, Jeremiah and Conrad are all still reeling from the aftermath of the canceled wedding — including them all being on mostly non-speaking terms.

On the anniversary of their mother’s death, however, the estranged brothers run into each other while visiting her grave, where they come face-to-face for the first time since Conrad’s last-minute confession to Belly the night before her and Jeremiah’s wedding day.

The brothers have a heart-to-heart about Belly, with Jeremiah even giving Conrad his permission to pursue his ex-fiancée. Jeremiah tells Conrad that while he shouldn’t expect him to be “okay” with it, he also doesn’t want him to waste their magnetic connection.

In the books, however, this conversation between Conrad and Jeremiah doesn’t happen — at least not to Belly’s knowledge. Instead, once the wedding is called off, Conrad keeps his distance for three years before writing to her during her junior year.

Laurel and John’s reconciliation

Given that it spans several months, a lot goes down in the second-to-last episode of the series — including Laurel and John’s apparent reconciliation. The pair reunited earlier in the season and seem to have found their way back to one another, but their romance is never rekindled in the books.

Conrad flying to see Belly in Paris

After receiving a sort-of blessing from Jeremiah and some encouraging words from Agnes (Zoe de Grand Maison), episode 10 ends with Conrad changing his flight to Paris at the last minute, presumably to tell Belly how he feels.

It’s a notable departure from the books, where Conrad never heads to Paris. As for what awaits him once he steps off the plane, fans will have to wait and see how the show wraps up in its final episode.