What did Tully do to Kate in Firefly Lane? All you need to know

Firefly Lane is back for another season on Netflix once again starring Katherine Heigl and Sarah Chalke as childhood besties Tully Hart and Kate Mularkey respectively and, following season one's big cliffhanger, fans are hoping that they get their answers.

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The second season, which landed on the streaming platform this week, goes into the main mystery that fans were left trying to crack at the end of season one: why did Tully and Kate fall out?

WATCH: Firely Lane season two is out now - official trailer

As fans know, Netflix's Firefly Lane is based on the book by Kristen Hannah of the same name – but if viewers were hoping to find the answers there, then they're in for a surprise. It turns out, what happens in the show is very different from what happens in the book, and far more dramatic, too. Find out the answers here but warning! There are spoilers ahead…

What did Tully do to Kate in Firefly Lane?

It all begins when Tully offers to babysit Marah, Kate's grounded daughter, so that Kate and Johnny can celebrate their rekindled romance alone.

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kate and marah in firefly lane
kate and marah in firefly lane

Firefly Lane is back for season two

While hanging out at Tully's apartment, Marah receives a text from a girl she's crushing on named Ashley asking to go on a movie date. Although Marah knows she's not allowed out, Tully takes pity on the teen and says she can go anyway.

Shortly after, Tully then has her own romantic moment after bumping into an old flame who now lives in her building. They share a pizza together but then Tully is disappointed when he then confesses he has a girlfriend.

After some wine, Tully then gets a call from a worried Marah who tells her she and Ashley detoured to a fraternity party where Ashley later abandoned Marah. Marah then ends up in a scary situation with a boy who won't leave her alone, this prompts Tully to then set out to rescue her.

sarah chalke as kate in firefly lane
sarah chalke as kate in firefly lane

Sarah Chalke as Kate

On the way home, however, more disaster strikes when they're involved in a car accident which hurts Marah and leads to Tully getting arrested. Despite apologising to Kate profusely, the mother tells Tully she doesn't accept her apology and that the friendship is over.

What happens in the Firefly Lane book between Tully and Kate?

The fallout in the book is very different. In the novel, when Kate turns to Tully for advice regarding her troublesome teenage daughter, Tully decides to bring the mother-and-daughter-duo onto her talk show, The Girlfriend Hour, to discuss the issue.

But during the segment, Tully somehow ends up putting her foot in it and makes out her friend to be a bad mother. This prompts Kate to cut off their friendship.

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