context: Anna (Emily Browning) has been in a psychiatric institution for ten months, following her suicide attempt after her terminally ill mother died in a boathouse fire. Upon her discharge, she has no memory of the event but frequently suffers related nightmares. While packing, Anna is startled by a disturbing, talkative patient from the room across the hall. Shortly after, she leaves with her father, Steven (David Strathairn), a writer who has dedicated his latest book to Anna and her sister.
  At home, Anna reunites with her sister, Alex (Arielle Kebbel), with whom she is very close. The sisters stand against Steven's girlfriend Rachel (Elizabeth Banks), who had been their mother's live-in nurse. Alex criticizes Steven for sleeping with Rachel while the girls' mother was still alive and sick in bed but he does not respond. Anna describes to Alex how scenes from her dreams have started happening while she is awake. The sisters become convinced that the hallucinations are messages from their mother, telling them that she was murdered by Rachel.
  Anna catches up with her old boyfriend, Matt (Jesse Moss), who tells her that he saw what happened the night of the fire. They secretly plan to meet that night, but Matt fails to show up and Anna returns home. In her room, Anna awakens to find him climbing into her window, saying that she needs to know the truth and that he had a warning from her mother. They kiss but then Anna notices Matt's body suddenly warping and his back breaking. Anna flees from the room in fear but when she opens the door, he is gone. The next morning, Matt's dead body is pulled out of the water, his back broken just the way Anna saw it. The police assume he fell and drowned.
  The sisters are unable to find a record of Rachel with the State Nursing Association and conclude she is actually Mildred Kemp, a nanny who killed the three children she looked after because she had an obsession with their widowed father. They try to warn their father, but he ignores their concerns and leaves for work. The girls try to gather evidence against Rachel to show the police but Rachel catches them and sedates Alex. Anna escapes and goes to the local police station, but they do not believe her claims and call Rachel, who sedates Anna and takes her home.
  As Rachel puts a disoriented Anna in bed, Anna sees Alex in the doorway with a knife and then passes out. She wakes to find that Alex has killed Rachel and thrown her body in the dumpster. Relieved, the girls comfort each other. Their father drives up, horrified at the scene. Anna explains that Rachel tried to murder her and her sister but Alex saved their lives by killing Rachel. Confused, Steven says that Alex had died in the fire along with their mother. When Anna looks down, she finds that she is not holding her sister's hand, but the bloody knife used to murder Rachel.
  Anna finally remembers what happened on the night of the fire. After catching her father and Rachel having sex, Anna became enraged and filled a watering can from a large gasoline tank in the boathouse, intending to set them and the house on fire. She didn't close the tap carefully, as a result of which a trail of gasoline spilled from it, which was then ignited by a falling candle. Her mother and Alex were killed in the resulting explosion. Flashbacks reveal that Anna had been hallucinating Alex since she left the institution. She remembers killing Mattâwho did show up at their planned meetingâby letting him fall and break his back. She also remembers killing Rachel.
  The police are called to arrest Anna for murder. When Steven is questioned, he reveals that Rachel changed her last name years ago to escape an abusive boyfriend, which explains why Anna couldn't find Rachel's record, and the Mildred Kemp story she came up with was false, implying Anna is mentally sick.
  At the institution, Anna is welcomed back by the patient across the hall that scared her earlier in the film, whose name plate on the door reads "Mildred Kemp".
question: At Windward house, Stella finds who in the studio?
answer: Her grandfather.