Claire Petersen is 24, addicted to social media, has one friend (April), she's overweight & lazy. She has bad skin & dull, limp hair and lies come easily to her. She works 2 mornings a week as a receptionist for a small medical office in midtown Manhattan. The other days, she spends hours scrolling on her phone & trolling people on Instagram.
As she's walking past an exclusive hair salon in the Upper East Side, she spots HER. What's SHE doing in New York? Claire follows HER to one of the nicest brick brownstone on East 63rd Street. It's one of the most expensive properties in Manhattan. Claire stays up half the night looking for Hannah Wilson on social media. Nothing on Facebook or Twitter. Nothing recent on Instagram. That's because she's married now & wearing a diamond ring with a stone the size of a small planet. Hannah is now Mrs. Carter living a charmed life. It's the life Claire used to have, before Hannah came along.
Over the next 10 days, Claire stalks Hannah. And, when Hannah fires her housekeeper, Claire fills the vacancy. She cuts her hair short, colors it & calls herself Louise Martin. It may have been 10 years ago, but it was a big case at the time. Wilson vs. Petersen. Claire's parents were being sued in civil court for sexual assault. Claire has held a grudge against Hannah for the past 10 years. With revenge on her mind, Claire tracked her down & inserted herself into her house under false pretenses. She has had to come up with all sorts of ways to hide her duplicity.
Claire (Louise) finds a diary in a hiding place in Hannah's walk-in closet around the same time Hannah tells Claire (Louise) that there's an issue with her W-4 form; the Social Security number doesn't match. Uh, oh! All she can think about is getting back to that diary. The entries are lies about Claire (Louise), inventing events that never happened, twisting the truth. She's being played but she doesn't know why & it's scaring her. It's a setup. All this time she thought she was the cat; turns out she's the mouse.