context: Jack Slavin (Daniel Day-Lewis), a Scottish farmer with a heart ailment, lives on an island which had been a hippie commune decades before. He is struggling to keep landowners from building developments on the wetland. His teenaged daughter Rose (Camilla Belle) is a beautiful but isolated girl with a passion for gardening. Since Rose's mother had left the family, Jack homeschooled his daughter and did not expose her to life beyond their small island home. Jack believes that they both "need a woman around." He travels to the mainland to ask his girlfriend Kathleen (Catherine Keener) to move in with him. Jack breaks the news to a shocked Rose, from whom he had kept his relationship a secret. Rose remains disdainful when Kathleen and her two teenage sons move in.
  Kathleen struggles to adapt to the Slavin's rural lifestyle. Her sons Rodney (Ryan McDonald) and Thaddius (Paul Dano) are almost polar opposites; Thaddius is a sullen, rude delinquent, while Rodney is insecure and often overlooked. While she still has a strained relationship with Kathleen, Rose develops strange bonds with her new "step-brothers." It is clear that Thaddius is attracted to her, but Rose does not like him. One night, Rose spies on Jack and Kathleen in bed together, and develops a strange jealousy toward Kathleen. Rose decides to lose her virginity, and shocks Rodney by confronting him topless and asking him for sex. Rodney refuses and reasons with her, and instead ends up giving her a dramatic haircut. Afterward, Rose calmly takes her father's shotgun and possibly misfires it into Jack and Kathleen's bedroom as they sleep. An initially shocked Jack confronts Rose in disbelief, but the two seem to forget the event within minutes.
  Kathleen asks Jack about his relationship with Rose, and how she might have psychological problems that should be dealt with. Jack denies that his daughter has any problems. Meanwhile, Rose and Rodney become good friends. Rodney is often criticized by his mother for being overweight, and the two fight constantly about his diet, but Rose sees only his kindness and intelligence. However, still on a mission to lose her virginity, Rose's thoughts turn to Thaddius. While trapping a copperhead intended for scaring Kathleen, Rose sees Thaddius and a girl named Red Berry having sex in the woods. Later that night, Thaddius enters Rose's room and though she dislikes him, Rose allows him to have sex with her. The copperhead, which Rose has kept in its cage under her bed, escapes into the house when the lock of the cage is loosened and drops open by the vibrations of the bed that Thaddius and Rose are having sex in.
  To irk her father, Rose hangs her bloodied bedsheet in the front yard. Jack is furious that his daughter has been "ruined," and gives Thaddius one day to move out. Meanwhile, Kathleen is cornered by the copperhead. The resulting chaos puts the whole household on edge. That night, Rose holds a screening of a homemade movie about the hippie commune in her treehouse. As the film rolls, Thaddius advances on Rose and is stopped by Jack. After a scuffle, Thaddius falls from the treehouse and is rushed to the hospital. Rose runs away and hides for days. Jack finally finds her, and offers to ask Kathleen to leave if it would bring Rose home. A distraught Kathleen demands $20,000 in exchange for leaving, which Jack pays.
  Jack returns to Rose's hideout, and she is overjoyed with the news that Kathleen is gone. That night, Rose kisses Jack, and the shock that his daughter is in love with him makes him upset, and he weeps. Waking the next morning, the memory of the kiss haunts Jack. He and Rose go to the house of the builder, Marty Rance, and Jack breaks down, finding that he has no fight left in him. He tells Rance to destroy the wetlands. He and Rose return home, and Jack dies within a few days. Rose had originally planned to kill herself when her father died, but after setting the house on fire and lying down next to Jack's body, she changes her mind and escapes.
  Two years later, Rose is shown living in Vermont and working in a greenhouse where Gray, her father's friend from the island, works as well.
question: Who demands $20,000 in exchange for leaving?
answer: Kathleen