What did Tully do to Kate in Firefly Lane? The answer to what we've all been dying to know

Netflix's Firefly Lane ended in a cliffhanger that left us wondering why best friends Kate and Tully broke up. So what actually happened?

Firefly Lane
(Image credit: Netflic)

Netflix's Firefly Lane has been our latest TV binge but what started out as a lovely wholesome watch has ended in a major cliffhanger that we're desperate to get to the bottom of—what did Tully do to Kate? 

*Warning* Contains spoilers.

The show, which stars Katherine Heigl as Tully and Sarah Chalke as Kate, is based on New York Times best-selling author Kristin Hannah's 2008 novel of the same name. It follows the two best friends, who have been inseparable since becoming best friends in the eighth grade back in 1974. For the past 30 years, their lives have become intertwined and co-dependent despite looking very differently—Tully is a high-flying journalist with her own TV talk show, while Kate gave up her career as a producer after getting married and having her daughter. 

However, Firefly Lane's ending left us all shook as it took us to the future, where Kate and Tully were no longer friends. Yep. 

Throughout the season, the show jumps between snippets from the women's childhood, their early 20s and the present day. In the last few episodes, we're then shown a flash forward to the future, where Kate is attending a funeral with her daughter Marah and it is here we see her come face to face with Tully, after it appears the two have been estranged. We're not told why but we do know that it has something to do with a major betrayal on Tully's part that Kate cannot forgive. So what exactly happened? Here's what we know... 

Firefly Lane

(Image credit: Netflix )

Why does Kate hate Tully in Firefly Lane?

According to the book, Kate and Tully fall out after Tully pulls a stunt that publicly humiliates Kate.

While it is safe to say that the TV adaptation differs from the novel in many ways, in Kristin Hannah's book Tully invites Kate and her daughter Marah onto her talk show, The Girlfriend Hour, for what Kate believes is an attempt to bring their turbulent mother-daughter relationship closer. However, she's soon horrified to find out that the segment is instead all about overprotective parents and is heartbroken when her best friend paints her as a bad parent live on national TV. 

While we know that in the show, Tully has resigned from her job at The Girlfriend Hour and plans to create her own show with Kate as her producer, could this incident still be played out somehow in season two? Potentially. Another thing we know is that it won't be Johnny (who Tully slept with before he got with Kate) who comes between the two women, according to Katherine Heigl. "It can't be that Tully sleeps with Johnny. I don't think that any friendship can come back from that. I'll fight to the death that it is not that," she told Oprah Magazine. We really hope she's right!

The whole situation happens when Tully shows up at Kate's father Bud's funeral, it feels like it is the first time the two have seen each other in a while, although it is unclear how much time has passed since they fell out. One thing that's clear though is that Kate is still furious with Tully. "No one wants you here," says Kate. 

It comes as quite a shock considering how close the women were. We've spent an entire season becoming invested in the three-decade-long evolution of their friendship, which has made them closer than sisters. Nothing has ever come between them before, not their family, not men and certainly not their opposite lifestyles, so it's hard to imagine what Tully could have possibly done to break a bond that was once so solid. 

"Don't you think you've punished me enough?" Tully asks when the two meet at Bud's funeral. Kate replies: "When I said that I could never forgive you for what you did, what did you think that meant?" 

She then adds: "Go home. Now. I don't ever want to see you again," before walking away. 

We'll have to wait for next season to find out for sure...