Rebecca is the main villainess of the 2015 Lifetime Movie The House Sitter.
She is played by Ashley Dulaney.
The movie opens with a young couple returning to her parent's home after a long time away, with their conversation implying that the woman is estranged from her family. The conversation also reveals that they had been renting out her old room to people. They go inside and find the house surprisingly clean and all the family photos gone, with the woman stating that they had "completely erased" her. The boyfriend then finds a cell phone covered in a red substance, which appears to be blood. However, they go into the kitchen and find a pie sitting out, which was the substance they originally saw. Noticing the streamers on the kitchen doorway, the couple assume the girl's parents had made a surprise party for her and rush in. The woman screams as she sees her parents' dead bodies, both tied to chairs at the table with a Welcome Home banner hung over the table. A voice (which would later be revealed to be Rebecca's) says "Welcome home" and the two turn around before the scene goes to black (Since we never see the couple again, it's safe to assume Rebecca killed them as well).
The movie then flashes forward to Rebecca arriving at the Lawrence home, which she is to house sit while the family is away on a trip to their lake house. However, the Lawrences (particularly the teenage daughter Amy) are all unable to enjoy their trip due to them still reeling from the death of their oldest daughter Lauren, who died when she fell through the frozen lake and drowned. After some consideration, Sara (the mother of the family) decides to end the trip earlier and calls Rebecca to inform her of their return. After ending the call, the camera reveals that Rebecca has all the family's photos laid out on the living room floor, showing that she was already become obsessed with the Lawrence family.
When the family returns home, Rebecca greets them with a chipper demeanor. As she asks dozens of questions, she asks where their oldest daughter was, having seen her in several family pictures. After Amy sulks out of the room, Sara reveals from what happened to Lauren, to which Rebecca provides sympathy.
After taking a phone call, Rebecca reveals to Sara that her next house sitting job can't accommodate her arriving early and thus, she has no place to stay for the next few days. Sara, feeling bad at not having given Rebecca enough notice of their early return, offers to allow Rebecca to stay at their home until her next job is ready. Rebecca refuses, not wanting to impose, but is eventually "convinced" by Sara. At dinner that night, Amy eagerly asks the family to pose with her for a selfie.
Rebecca then tries to talk and bond with Amy, but her constant questions and quips make Amy uncomfortable. Later on, after having a nightmare about Lauren's death (which Amy witnessed), Amy wakes up to find Rebecca standing over her bed, claiming to have been trying to wake her up. Later in the day, while asking about any crazy things Rebecca had seen while house sitting and saying that "everyone has secrets", Rebecca responds by breaking a plate, which unnerves Amy. Rebecca also surprises Kyle (the father) by saying "Hi Dad!" to him as she passes him down the stairs (though she claims to have just been acting silly). However, Rebecca begins to bond with Sara over her hobby of remodeling antique furniture, earning her friendship.
Amy begins to grow suspicious of Rebecca, especially after they go on a trip to an antique shop with Sara, where the elderly shop owner recognizes Rebecca and refers to her as Claire. Rebecca claims that the woman has mistaken her for someone else, but she swears to Amy she looks exactly like someone who stayed with some friends of hers in another town and that she "had an angel on her shoulder". Before Amy can ask further questions, Rebecca pulls her away to show her a piece of furniture.
Amy later voices her concerns about Rebecca to her boyfriend Travis, who remains disinterested despite Amy's worries. That night, Rebecca returns to the pawn shop under the excuse that she saw a locket she wanted to get Amy. However, as the shopkeeper turns to get it, Amy pulls out a syringe and injects it. As the woman begins to feel strange, Rebecca says she does recognize her and gleefully wishes her a good day before walking out as the woman collapses. Then, when Rebecca returns home, she drugs Amy's water bottle, who has returned home early from a concert after having an argument with Travis. Amy drinks the water and passes out while writing an email trying to find more information on Rebecca. When Sara returns home, Rebecca tells her that she thinks Amy came in drunk and that she's worried that she's mixing alcohol with her medications (Amy takes sleeping pills, which Rebecca found while looking through her room). Sara checks in on the passed out Amy, clearly worried for her daughter's well-being.
The next morning, Sara confronts the groggy Amy about what she believes happened, leading to a disagreement between the two. Rebecca slowly begins to bond with Kyle as well, but Amy continues to be suspicious. She discovers that the people the shopkeeper claimed Rebecca lived with died in a house fire and meets their surviving son to talk to him. He describes Rebecca as "not right" and that she grew close to his family very quickly, but disappeared after the fire. He warns Amy that, if Rebecca was staying with them, they're in danger.
During this time, Rebecca has dressed herself up in Amy's clothes and invited Travis to the house, where she then seduces him. The two have sex, during which Rebecca takes risque pictures with Amy's phone. Later on, when Sara and Rebecca are looking through Amy's room while trying to find her, Rebecca "finds" her phone and feigns shock after finding the pictures. Sara is shocked and angrily confronts Amy about the photos when she returns home. Amy then accuses Rebecca of it and reveals everything she had found out about her. Rebecca then tries to cover her lies by saying she had a twin sister named Claire who had died in the house fire. But when Amy finds another hole in her lie (the newspaper article she found never mentioned anyone else dying in the fire), Rebecca breaks down in tears and leaves the room. Sara still isn't willing to believe Amy, which causes a fight between them where Amy reveals that she feels Sara blames her for the accident that killed Lauren. Sara denies this, but Amy insists it's the truth and flees the house as Rebecca watches from the upstairs window.
While Sara and Kyle search for Amy, she returns home to warn them about Rebecca. While she looks for them, she finds a photo album in Rebecca's room filled with photographs of her with other families. Rebecca walks in on her and Amy confronts her, wanting to know who she is and why she's been doing this. She claims she just wants to belong, and Amy tells her she's going to expose her as a fraud. But as Amy walks past Rebecca to leave, Rebecca knocks her out with a rolling pin, stating that she thinks replacing Amy will be really easy.
Amy wakes up in the basement, where she finds Travis's body. Rebecca explains that she hadn't planned on killing Amy, having been looking forward to having a sister. Amy tries to scream for help when she hears her parents' car pull into the driveway, but Rebecca knocks her out again and goes upstairs. She tries to make dinner for Sara and Kyle, but they remain adamant on finding Amy. Rebecca then begins to slip, talking about how ungrateful Amy was and how she doesn't deserve to be a part of the family. Sara and Kyle finally see how unstable Rebecca is and demand she tell them where Amy is, but Rebecca responds by stabbing Kyle and then tying the two to chairs at the dinner table, forcing them to have a family dinner. Meanwhile, Amy wakes up and starts looking for a way to save her family.
During dinner, Sara begs Rebecca to get Kyle help, but she ignores her and engages in normal conversation while holding a gun to Sara and Kyle. But while Rebecca is in the kitchen getting food, Amy hurries in and tells her parents she's going to get them out of this. When Rebecca returns, Sara begins to play along to Rebecca's delusions, but Rebecca somehow senses Amy's presence and walks to the kitchen doorway to find Amy with a gun. Amy demands she let her parents go, but Rebecca taunts her with her sister's death, accusing her of letting Lauren drown. Amy slips and falls, allowing Rebecca to get the upper hand. But just before Rebecca can kill Amy, Sara frees herself and knocks Rebecca out with a bottle.
We never find out what happens to Rebecca, but it can be inferred that she was arrested.