Plot
A young girl named Ida and her older sister Anna, who has nonverbal autism, have moved into an apartment with their parents. One day, Ida meets a young boy named Ben, who possesses telekinetic and telepathic abilities, and the two strike up a friendship. While hanging out with Ben, Ida becomes disturbed when he kills a stray cat by crushing its skull after dropping it from the top of the apartment complex's stairs. Ida later meets another girl, Aisha, who has similar abilities to Ben. Anna is later revealed to also have powers and eventually begins to tentatively speak with Aisha's support, much to the joy of her parents. Anna, Aisha, and Ben's powers are strongest when the three are together, with Ida seemingly being the only one in the group who lacks powers.
The children become close friends and practice their powers to strengthen them. However, their friendship is soiled when Ben becomes angry at an insulting telepathic message and injures Anna. Later at home, Ben assaults his abusive mother and eventually kills her, leaving her body in the kitchen.
Ben starts to become increasingly erratic and violent, eventually using his powers to manipulate a neighbor into murdering a bully who had earlier harassed him and Ida. He later confides his mind control abilities to Ida, who initially does not believe him until he causes her to climb on top of a refrigerator, where she hallucinates a snake that Ben claims he did not create mentally. Later, Aisha confronts Ben after he telekinetically snaps the leg of another young boy, causing another fight between the two of them until Ida intervenes. The girls resolve to stop Ben to keep him from hurting them and other people. That night, however, Anna and Ida are not allowed to leave their apartment by their parents, and Aisha is murdered by her mother, who is being manipulated by Ben; consequently, Anna loses her ability to speak.
Ben seemingly tries to kill Anna and Ida next by manipulating a stranger, who unsuccessfully tries to follow them into their apartment. In an attempt to stop Ben, Ida invites him to play with a toy glider and brings him to the highway overpass where the bully was killed, before pushing him off the ledge when he is about to throw the glider. Ben survives the fall and Ida runs off, but soon realizes she is under Ben's control when her surroundings become dark and twisted. Ida runs into the road and is hit by a car; simultaneously, Ben wakes up screaming.
Now stuck at home, Ida is afraid that Ben will manipulate her mother into murdering her and locks herself in the bathroom. Her mother instead leaves to go to the store, and, when Ida leaves the bathroom, she finds that Anna has also left the apartment. Ida loses her crutch while trying to get down the stairs, and, when she screams in pain, her cast cracks open, showing that her leg has healed and revealing that she too has telekinetic powers. Ida goes outside and finds Anna and Ben battling on the shores of a large pond as nearby children watch on. Ben initially gains the upper hand, but his powers weaken as the sisters work together to defeat him, and he is eventually killed by a big burst of energy.
Ida and Anna go back to their apartment and sit in silence until their mother returns home. While playing with her scribble-board, Anna pauses briefly, as if she is about to write something, which suggests she may regain the ability to communicate with Ida.
