None of This is True

The paths of two women — Alix Summer and Josie Fair — cross when they are out celebrating their birthdays in the same restaurant.
Big coincidence: they are birthday twins; not only this — they were born in the same hospital.
Alix is a journalist and podcaster. Could this be her next subject, she wonders: the story of two women who share the same birthday but whose lives could not be more different. She proposes this to Josie, and they start sharing their stories in Alix's recording studio.
But slowly Alix starts to realise that Josie has been hiding some very dark secrets, and before she knows it Josie has inveigled her way into Alix's life — and into her home.
Soon Alix starts to worry that Josie will never leave.
But, as quickly as she arrived, Josie disappears. Only then does Alix discover that Josie has left a terrible and terrifying legacy in her wake, and that her family is in more danger than she ever thought possible ...