Eve Goode (Angie Harmon), who lives in an isolated Spanish-style house not far from Los Angeles, cleans her oven. When her husband Raymond (Joel Gretsch) informs her that their young son, David, is missing from his room, she washes her hands and neatly folds the towel before joining the search. Eve and Raymond are shown running, with Raymond yelling for David, and ending with Eve crying, screaming for David.A year after the loss of David, Eve and Raymond become the foster parents of a recently orphaned boy named Ethan Snow (Bobby Coleman) and his teenage sister Abby (Jordan Hinson).Abby and Ethan would rather live with Ben Koch (Jason London), a cop who has known them all their lives via his friendship with their parents, and cares deeply about them. He'd love to take them in, if he felt that he was qualified or capable of raising them, but he lives in a one bedroom apartment.Abby and Ethan are soon swept away by the wonderfulness of their new foster parents, and the incredible house that is their new home.Ethan gets his own room with a bathroom close to the master bedroom, but Abby gets the bedroom that's the farthest from Ethan's room, in a part of the house called the tower. A flight of metal stairs outside the tower leads up to the door.The too-good-to-be-true façade begins to crumble as Eve, who seemed kind and compassionate at first, gradually reveals herself to be a domineering, obsessive woman who controls Abby and Ethan's every move, and allows them no freedom whatsoever.There is even a code number that must be dialed before they can make any phone calls, and Abby and Ethan are not told what the code is. Eve even has double locks put on all doors that lead outside.Raymond tells Abby that David had drowned in the lake that the house overlooks. Abby becomes suspicious, especially when she finds an old bed in the basement, and David's name carved on a support post right by it.Ben visits, and Abby begs him to get her and Ethan out of there, but Ben tells her to give it a little more time, saying that he'll take Abby and Ethan to Six Flags in a couple of weeks. When a case worker (Tasha Smith) visits to check up on everything, David's bed is no longer in the basement.What Abby discovers is that Eve is highly unstable. While doting on Ethan, Eve competes with Abby for his love, and develops a spiteful and increasingly violent relationship with Abby as Abby grows more and more rebellious because of her suspicions of Eve and Raymond.The violence starts with Eve slapping Abby for using a four letter word against her. Eve even causes Abby to cut her arm deeply by deliberately leaving already-broken glasses in a sink full of dishes that she tells Abby to wash.The dishes were covered by a thick layer of soap bubbles, so Abby didn't see the broken glasses. Eve, who used to be a nurse, stitches the wound, deliberately making the process as painful as possible. And she injects Abby with something. Abby later wakes up, feeling not-so-good, and Eve tells Abby that she was in bed for three days.When Ethan comes down with a mysterious illness that Eve insists on treating at home, Abby is suspicious that Eve is spiking Ethan's food with something in order to make him sick.Ethan grows sicker by the day, and both of their lives are in grave danger as Eve grows more and more unstable. Abby insists that Eve take Ethan to the hospital, but Eve refuses.Abby searches the Internet for information, and learns about Munchausen syndrome by proxy. Abby is horrified to realize that Eve's behavior perfectly fits every symptom that's listed on the website -- including the one that says that those who have Munchausen syndrome by proxy are skilled deceivers. The site even says "Suspects should be considered even more dangerous once they believe they are suspected."Abby tries to use the computer to send an e-mail, but that feature has been blocked, so she tries to use it to dial 911, but that has also been blocked.When Abby talks to Raymond, he tells her that David was a foster child, like she and Ethan are. Abby is deeply disturbed that the picture of David that Raymond is holding is not the same picture she found during an earlier visit to David's bedroom.Abby once again goes to David's bedroom, where she finds a picture drawn by a boy named Tyler, and learns of the existence of another boy named Alexsei. Abby grabs some pictures of them as evidence.It seems that Munchausen syndrome by proxy has led to Eve killing a number of foster sons. Abby realizes that she and Ethan have to save themselves from Eve before she can kill them.Abby gets Ethan, who is still sick, outside of the house and inside of a car, and then Abby sees Raymond returning home. Abby rushes Ethan back to his bedroom. Abby promises Ethan that she'll go get Ben, and bring him back with her.In a hallway, a furious Eve finds Abby, and shakes her, causing the pictures to drop to the floor. Eve viciously smacks Abby, drags her into the nearby attic, kicks her to the floor, and locks her in.After a while, Eve brings some food to Abby, and leaves. Abby thinks it might be spiked with whatever's making Ethan sick. Later, Eve comes back in and tells Abby that if she doesn't eat, then Eve will never let Abby out of the room.Later, Eve leaves another meal in the room, and walks away. Abby grabs a screwdriver, and starts trying to pry off the board that covers the window. Later, Eve injects Ethan with something, and then she sprays heavy-duty oven cleaner on his back to make it look like a rash has appeared.Abby pries the board off, and she sees Ben pulling in. Raymond comes in, and tells Abby that if she makes one sound, he'll kill Ben. Raymond answers the door and tries to make an excuse to keep Ben from coming in, but Ben wants to come in and look around. Ben asks where Ethan's room is, and Raymond leads him to a bedroom that no one is in.Ben, who is becoming suspicious, decides to leave, and Abby is trying to pry the window opened, and she manages to cut away a small section of glass. Raymond, who heard the sound of the piece of glass dropping, goes back in and tells Eve that Ben left.Abby breaks out the rest of the window, and gets out of the attic. Abby goes to Ethan's room, and Eve, listening via an intercom, hears Abby telling Ethan that they're getting out of there.Eve goes to the kitchen, grabs a meat cleaver, and goes to Ethan's room, but she doesn't see Abby. Eve starts searching for Abby, who goes outside. Eve goes out onto a balcony, and sees Abby. The phone starts ringing, and Eve gets to it first. It's Ben, who immediately hangs up.Ben, who is just down the hill from the house, has started suspecting Eve and Raymond of child endangerment, so he called to make sure they're home. Ben alerts his colleagues at the LAPD. Over the house's intercom, Eve tells Abby that she's not going anywhere.Abby goes out to the garage, and starts up the SUV, but she gets out of it so she can open the garage door. Raymond grabs her, throws her down, and tells her that she just can't leave.Abby hits Raymond on the head with a wrench, knocking him out. Abby runs, and Eve finds Raymond out cold. Eve turns off the SUV, and takes the keys. Eve walks away.Ben finds Raymond out cold. Ben goes inside, and Eve stabs him in the neck with a hypodermic needle, injecting him with something that makes him collapse. Abby goes back to Ethan's room, and he's not there.Abby hides under the bed when she hears Eve coming. Eve doesn't find Abby in the room, so Eve leaves to continue searching. Abby gets out from under the bed. Eve goes to Abby's room, and Abby hears her telling Ethan to stay there.After Eve leaves Abby's room, Abby heads to the room, and doesn't see Ethan there. Eve has tricked Abby into coming out of hiding. Eve comes in with the cleaver, and they struggle with each other. Abby forces the cleaver out of Eve's hand.They end up on the landing at the top of the stairs to the room, where Eve tries to push Abby over the railing. But Abby knocks Eve down the metal stairs, and Eve takes a blow to the head.Ben wakes up, and he sees the needle that Eve stabbed him with. Abby finds Ethan in a bathtub of hot water, with his face partially submerged. That's how Eve made it look like David drowned in the lake.With the bathtub filling, Abby gets Ethan out of the tub, and realizes that he's conscious -- he didn't breathe in much water at all. Eve comes up behind Abby, who screams.Eve knocks Abby to the floor, and raises the cleaver. Ben enters with a gun. Before Eve can hit Abby with the cleaver, and before Ben can fire his gun, someone else fires a shot that kills Eve.It was Raymond who fired the shot. It seems that the reason why Raymond reluctantly helped Eve is because he was so blinded by his love for her. Raymond is arrested for his part in endangering Abby and Ethan.Abby and Ben ride to the hospital in the ambulance with Ethan. They'll be living with Ben.