| Director | William Friedkin |
|---|---|
| Budget | $10 million |
| Box office | $17 million |
Molly and Allan Sheridan leave their two children in the care of a new nanny, Diana Julian. Diana, who is in fact an ancient Hamadryad, kidnaps their infant daughter, taking her to a forest where she approaches a giant, gnarled tree, serving the child as a human sacrifice to sustain the tree's life. As she stares into a pool of water, Diana's reflection transforms to that of a growling wolf.
Three months later, Phil and Kate Sterling have recently relocated from Chicago to Los Angeles, where Phil has taken a lucrative advertising job. Kate becomes pregnant, and gives birth to a son, Jake. The couple decide to hire a nanny to allow each of them to maintain their jobs, and interview two candidates through a nanny agency: a young woman named Arlene, and a caring English woman, Camilla. When Arlene dies in a bicycling accident, Camilla is swiftly hired and becomes an invaluable member of the Sterlings' household.
One afternoon while Camilla rests in a meadow with Jake, she is approached by three aggressive bikers (Outlaw motorcycle club) who attempt to sexually assault her. She flees to the base of the gnarled tree, which subsequently comes to life, its branches strangling and eviscerating the men. Wolves consume the entrails of one of them, and another is impaled by the tree's root and then bursts into flame. During a dinner party some days later, Ned, the Sterlings' neighbor who designed their home, invites Camilla on a date, which she declines. That night, Phil has a nightmare in which he has sex with Camilla. The next day, moments after Camilla leaves to go shopping, Ned stops by the house with a bouquet of flowers for her. Kate explains she just left on foot, and Ned drives after her, catching sight of her fleeing into the forest. Ned pursues her, eventually coming across her bathing in the creek. He watches as Camilla approaches the large tree, and begins to fuse with the tree bark. A pack of wolves pursue Ned, who flees back to his house. He leaves a rambling phone message for Phil and Kate. Moments later, Camilla appears, naked and ashen, on the hearth, telling Ned that he should not have followed her before the wolves break into the home, eating him alive. Camilla drags his remains away.
When checking the answering machine the following morning, Phil finds two messages: One from a stranger, Molly Sheridan, who says it is urgent she speak with him. The next is Ned's, which is incoherent, but Camilla interrupts him from finishing listening to it. Phil meets with Molly the next day. She describes the disappearance of her infant daughter, as well as the nanny Diana, whom she came to discover to have been a false identity. She requests that Phil arrange for her to see Camilla, suspecting they are the same person. When Phil returns home, he listens to Ned's message in full, which warns him against letting Camilla back in the house. Discovering Ned is missing, Phil confronts Camilla in front of Kate, but Jake grows violently ill during the confrontation and has to be rushed to the hospital, exhibiting coma-like symptoms.
Jake regains consciousness in the hospital, and Camilla attempts to kidnap him, but Phil intercepts, backhand slapped Camilla to the ground. Phil and Kate depart with Jake, and upon arriving home are confronted by a pack of wolves. Kate flees to the couple's Jeep, while Phil runs toward the woods with Jake, as Camilla pursues them both, levitating through the forest, until they reach the large tree. Kate chases after them in the Jeep, eventually hitting and seemingly killing Camilla. As Phil examines Camilla's body, he notices faces of babies embossed in the tree bark.
Later, a detective tells the couple no evidence of Camilla's existence can be found. Phil decides to cut down the tree with a chainsaw, but in his absence, Kate is attacked by Camilla—now part-tree, part-human—who has again infiltrated the house. As Phil attempts to cut the tree, the branches entangle him and begin to bleed as he inflicts damage on them. The damage concurrently impacts Camilla, who is fighting Kate. When Phil saws off a large branch, Camilla's leg severs from her body, allowing Kate to push her out a window. Simultaneously, Phil manages to fell the tree, but it combusts before landing, as Camilla's body similarly disintegrates before hitting the ground. A bloodied Phil drops the chainsaw and returns home as Kate picks up Jake. Seeing the mess in the house, Phil realizes what happened as he is reunited with his wife and son, now knowing that with Camilla finally dead, his family is now safe.