Part One:

Lucas just got off the phone with his friend who informs him his step-sister is going out with his friend, Tommy. He tells her she can't go out with him, he's just going to try to fuck her and make her into a slut. She gets pissed off and they start fighting until Kylie eventually goes to bed. Lucas isn't ready to let this go, and he's going to show her what a slut really is

Part Two:

Kylie just got out of the pool and she's laying out in the sun when she realizes Lucas has been watching her. He asks if she's been seeing anyone, to which she replies no, you told me not to. He grabs her and throws her down on her knees, make his cock into her mouth. Then, he grabs her by her hair, dragging her inside to fuck her on the couch. While he's fucking her, he makes her call her boyfriend and break up with him.