Mark decide to leave. Then he mistakenly calls Sheila "Mrs. Tierney", before quickly correcting himself. Sheila now understands the initials on the tree. PT is Philip Tierney – her husband's real name. She asks Philip about his name and why he lied about the nightmare house. He admits everything and tells her that the two years she had spent in a Swiss sanatorium were not due to tuberculosis, as she thought, but because at age 7 she had had a nervous breakdown. The only way Sheila will be cured is to discover why she blanked out her memories. But to do so, she will have to go into the attic, the room that terrifies her. She will not go, so Philip stomps off in anger. Jonah tells Sheila that at midnight, on the same day 17 years earlier, Matthew Tierney – Philip's grandfather – killed his sons Lawrence and Samuel in the attic with an axe. He then died. Samuel was Philip's father and Philip is the last of the Tierneys. Mark convinces Sheila that Philip is trying to drive her mad. He says that he and Jonah will stand guard outside the bedroom. After being jolted awake by footsteps and screaming, she opens the door and sees Jonah fall from the stairs, to his death. Philip declares that Mark killed Jonah. Philip starts their car – which he himself had disabled – and tells Mark to head for the police station, as he is unfamiliar with the local roads. Mark leaves, and Sheila locks herself in the bedroom. Philp bursts in and taunts Sheila to shoot him, to no avail. She loves him but believes he is becoming insane and asks to let her help him. He agrees, but only if she does whatever he says. He drags her to the attic, where she finally remembers witnessing the murders as a child. The recovered memory cures her on the spot. Sheila also suddenly knows that Jonah was the one who killed the Tierneys, insanely jealous of their wealth and wanting it all for his son, Mark. In the attic, Mark attacks Philip with an axe. As they fight, Philip throws him onto the axe's pick end, impaling him on the point. While leaving the mansion, Philip summarizes the situation for Sheila. A guilt-ridden Jonah paid for her to go to Switzerland after the murders. Mark killed Jonah before he