The Forest (2016)

Sara Price receives notice from Japanese authorities that her twin sister Jess is presumed dead, after entering Aokigahara forest, a place frequently chosen for suicide. Despite her fiancé Rob's concern, Sara travels to Japan and checks into the hotel where Jess was last staying.

At the hotel, she meets Aiden, a travel journalist, and they quickly bond with each other. Sara confides that her parents died in a car crash right outside the family home; Jess saw the bodies while Sara did not. Sara attributes her sister's mental health issues to this episode and regrets not "sharing the burden" by looking at the bodies as well. Aiden reveals a similar relationship, as his brother lost hearing in one ear as the result of a fight Aiden did not join. He now feels obligated to always help his brother in a manner similar to Sara with Jess.

Aiden then offers to accompany Sara into the forest along with a local guide, Michi. In exchange, Sara permits Aiden to write an article about her search for Jess. Michi warns that people who enter Aokigahara often carry emotional pain and may be vulnerable to supernatural forces. However, he also says that these forces can create illusions, in order to cause victims to hurt themselves.

While searching the forest, the group finds a yellow tent that Sara recognizes as Jess's. As night falls, Michi advises them to leave a note and return in the morning, but Sara insists on staying. Aiden stays with her. That night, Sara hears noises and follows them, encountering a mysterious girl named Hoshiko, who warns her not to trust Aiden and implies he is lying about Jess. Hoshiko flees and Sara falls over trying to follow, severely cutting her hand.

The next day, Aiden insists on escorting Sara out of the forest to receive medical attention. Sara is now suspicious of Aiden, and when he seems to be acting deceptive about their route, she confronts him. Aiden maintains that he never met Jess, but Sara forces him to admit that he lies about having a brother in order to get close to her. Sara revokes permission to be used in his story and demands his phone so she can delete audio recordings of her. Sara sees a photo of Jess on the phone and starts to believe Aiden is involved in her disappearance.

Sara runs from Aiden but falls into a cave, where she encounters Hoshiko again who reveals herself to be a yūrei, a malevolent spirit. Sara narrowly escapes Hoshiko, but finds a flip camera in the cave that shows images of her father's murder-suicide of her mother, revealing that Sara lied to Aiden about her parents' death. Aiden soon finds her and helps her out of the cave, with Sara telling Aiden she realises the mountain made her see a photo that did not really exist. Meanwhile, Rob arrives in Japan and joins Michi and a search party to locate the sisters.

Aiden leads Sara to a ranger station he claims to have suddenly found. While Aiden tries to fix the radio set, Sara notices a locked door from behind which she hears Jess's voice, and they pass several notes that implicate Aiden as her kidnapper. Sara stabs and kills him, only to realize that Aiden was innocent: the voice and note were more malevolent illusions. Sara then sees a vision of her father's ghost, it grabs her wrist and she escaped only by severing his fingers. She runs through the forest and sees Jess approaching the search party in the distance. Sara calls out but is not heard. It is then revealed she has fatally injured herself attacking the illusion of her father, and she never escaped the basement where she dies and yūrei drag her into the ground.

Jess, very much alive, is rescued by the search party and explains that the "feeling" of her sister is gone, and it is assumed that Jess knows Sara is dead. As the search party leaves, Michi spots a dark figure in the forest and realizes it is Sara, now a vengeful yūrei.