After a fight with breast cancer, Kate passes away at the conclusion of Firefly Lane Season 2. In Season 2 Part 1 ended in December 2022 with the tragic revelation that Kate from the ’00s has late stage breast cancer, which is a crucial plot point in Part 2.
Kate decides against undergoing any more arduous treatment as the cancer has progressed to her brain and begs Tully, who is determined to enrol her best friend in clinical trials, to “let go,” as the cancer has moved to her brain. She makes the decision to finish the writing project she’s been working on and spend her final days with her loved ones by her side.
Kate’s best friend Tully (Katherine Heigl), daughter Marah (Yael Yurman), and husband Johnny (Ben Lawson) were all devastated by Kate’s passing. She did, however, depart on her own terms. She patched up her strained friendship with Tully, wed her ex-husband Johnny again, and finished writing her autobiography in the final weeks of her life. She made arrangements for Johnny to give Tully the manuscript after she passed away.