Sarah Flynn is Candace Flynn's twin sister in the Ferb Fletcher, the Boy Who Lived: A Crossover series. She is not related to Phineas or any of the other Flynns, besides Candace. (Candace is not related to Phineas in the story, and is also Phineas's age.) She also appears in the fanfiction Jeremy's Moving Castle, where she is Candace's younger sister instead of her twin. Chapter 1 The Time Machine Of The Twin Sister Chapter 2 Sarah Flynn Is Here Peace!