Like Season 1, the show jumped around in time for Season 2’s first half, with the 1975 timeline melting into the present day, only to jump back and forth between 1986 and 2003. That wasn’t the case for the novel, which tracked Tully and Kate’s relationship from their first meeting in 1974 through the end of their friendship in the mid-aughts in linear order.

The show sliding around in time meant that it was a far more prominent jump in time when the school year moved from one grade to the next. But the show didn’t just highlight Tully’s return to living with Cloud on Firefly Lane mid-semester in 1976 by making it a time jump. It also changed the reasons for it. In the show, Cloud gained her sobriety. When she came to take custody of Tully from Gran again, their living situation had become toxic, with Tully drinking, getting high, and acting out. Gran screamed that Tully is as sinful as Cloud as they left.

That’s not how it went down in the novel at all. Like in 1974, Tully didn’t want to move back in with Cloud; she had no choice. Gran passed away, leaving Tully grieving the only adult in her life while stuck again with her hot mess of a mother.

In the novel, Kate, Tully, and Johnny are in a love triangle. Johnny crushed on Tully, Kate crushed on Johnny, and Tully crushed on herself. Kate only got Johnny’s attention while Tully was on leave after the incident when Tully was shot on camera (depicted in Season 1 of the show). By the time Tully returned, Kate had Johnny on lock, and the two were all but headed for the altar.

The show changed this completely. Though Kate feared a love triangle, it was all her insecurities talking; Johnny never had eyes for anyone else, telling Kate he only hesitated because he knew it would be forever once they got together. Kate’s breakup with Johnny over marriage never happened in the book either.

Much like Kate’s expanded love life, Tully’s relationship with Danny was also massively expanded for the series. In the novel, Tully never settled down — one of the reasons Kate secretly feared Johnny would leave her for Tully — and reporters like Danny were all one-night stands.

The show expanded the Danny relationship to a “one that got away” for Tully, partly to put more of Tully’s decision to go to Antarctica onscreen. (In the book, she’s “in Antarctica” when Kate needed her most, and how she decided to go there isn’t relevant.) Danny adds a further wedge into the original triangle, making it much more apparent that “Tully and Johnny” were always just in Kate’s imagination.

This was a fascinating change from the novel that stemmed from having Cloud barrel into Tully’s 2003 life in Season 1. In the book, Tully hadn’t seen Cloud in decades, but Cloud didn’t voluntarily reappear. The viral video series Tully started, which eventually got her The Girlfriend Hour, was her search for her mother.

The show reversed all that. Tully started her blog and video series after losing The Girlfriend Hour, and instead of looking for mom, she was searching for the dad Cloud refused to talk about. Some of that is taken from the Firefly Lane book sequel, Fly Away, and repurposed to fill out Tully’s story more thoroughly onscreen.

In the novel, Johnny and Kate never got divorced in the first place — that was all added for the show. That means Johnny never partnered up with Lottie in the field in Iraq — and almost in the bedroom — in the book.

But with the series doing the most to break up the Johnny-Kate-Tully love triangle, it left Kate with no one to passive-aggressively fight with for Johnny’s affections, especially in the added divorce portion of the timeline. Enter Lottie, which the show added wholesale to give Kate a rival from the 1980s who was not Tully. Instead, she got the girl who Kate at first laughed off, only to feel inadequate next to when she returned in 2003.

Episode 4 of the series, “Papa Don’t Preach,” added a new timeline to the show, with a one-episode pit stop in 1993. In it, Tully was struggling to make it alone in New York while Kate was struggling to conceive a sibling for Marah. Tully wound up giving Kate a pep talk, telling her that only having one child didn’t make her less of a woman, and she and Johnny would be happy with Marah even if they never had another.

Although the book does also pass through 1993, Kate was not struggling with fertility. In the novel, Marah has two younger siblings, twin boys, who were the nail in Kate’s working-mom coffin.

This is the biggie. As previously noted, Kate and Tully’s falling out in the book had nothing to do with a car crash — it all happened live on The Girlfriend Hour instead, when Kate tore down Tully’s reputation live on air because Tully accused her of being a bad mother.

The show changed that to something more understandable — a not-totally-sober Tully got into a car crash with Marah in the passenger seat on the way home from rescuing the girl from a frat party, leading Kate to cut her out of her life.

However, Tully getting into a car crash *is* something from the book — but not Firefly Lane. Tully’s near-fatal crash happened in Fly Away. The show borrowed that and repurposed it.

Finally, there’s Tully’s comeuppance. Tully was legitimately in the wrong regarding the car crash, even though she thought she was doing the right thing. That gave the show a reason to make Tully humble herself, admit she’d screwed up, and apologize.

In the book, Tully never begged Kate for anything. Because The Girlfriend Hour came down around Tully’s ears post-fight with Kate, she felt justified that she wasn’t in the wrong. If anything, Kate owed her an apology.