A happily married woman is terrorized by her psychotic neighbor when she refuses her advances. 

Following a house fire, the Peterson family is forced to live in a trailer until they get back on their feet. When Emily learns that her sister died recently, she grieves like any sister would, though her relationship with Stacey had been estranged and they hadn’t seen each other in a while.

Everything Stacey owned is left to Emily, including her gorgeous mansion with an in-ground pool. Emily’s kids, Lily and Josh, are overly excited to live in such a vast space while Emily and her husband Steve are worried about whether they can afford it. They decide to take a chance and the family moves in.

On their first night in the house, they meet the couple from next door - Carol and Mindy Winters, a same sex married couple. Mindy has an instant liking for Emily and takes her out for a day on the town. She also gives Emily a key to their house in case of an emergency. Mindy lies about Carol leaving her in order to gain Emily’s sympathy. When Emily least expects it. Mindy forcefully kisses her, upsetting Emily greatly, to the point that she throws Mindy out.

Things change drastically between the neighbors as tension flares. Innocent pranks by Mindy, such as ringing Emily’s doorbell and disappearing before she can answer turn much more serious when Mindy tells Carol that it was Emily who came on to her. Someone hacks into Emily’s facebook account and makes a post under her profile on Mindy’s page condemning homosexuality and sounding threatening. While Steve and Emily know Mindy was behind it, they have no proof.

Emily receives many negative responses for her comment but even worse, Mindy and Carol call the police over the incident. Unable to prove she didn’t make the post, Emily spends a night in jail for menacing. Upon her return home, Mindy continues her psychotic game, first by going swimming with the kids uninvited, then flattening Emily’s tire so she can go in her place to pick up the kids. The police can’t do much because the kids went with Mindy voluntarily.

Steve thinks it would be a good idea to go to the lake for a relaxing day. Emily decides to stay home and when she sees Mindy leave her house, she uses her key to go in and look for something to prove her innocence. She finds messages between Stacey and Mindy that prove they were having an affair. Mindy returns and holds Stacey prisoner. 

When Steve comes looking for her, he falls with a knife to his back. Knowing her life is in her hands, Emily battles against Mindy, who has also killed Carol as well as the hacker she paid to hack Emily’s social media. Mindy wins the fight and watches with the kids as Steve is taken away in an ambulance, expected to recover.