Incidents Around the House

Bela lives with Ursula, whom she calls Mommy, and Russ, whom she calls Daddo. The story is narrated by Bela, who wants her parents to be happy and is particularly close to Russ. A figure called Other Mommy emerges from Bela's closet. Bela initially regards it as a friend, but it begins to appear more often and persistently asks permission to enter her heart. Other Mommy tells Bela that if she agrees they will switch places: Other Mommy will live as Bela and Bela will go to the place the visitor came from. This is the figure's claim, not a mechanism Bela or the adults have established.

The encounters extend beyond Bela's bedroom. At a playground, Bela hears a voice resembling her friend Deb's, although Deb is elsewhere, and falls down a slide while retreating. At her parents' party, Marsha reports seeing a large, dark-blue, hairy figure, which Bela identifies as Other Mommy. Ursula questions Bela about these reports. Later, Bela hears someone who seems to be Mommy speaking about infidelity and unhappiness with family life, but the real Ursula appears in the bedroom and sees Other Mommy. The supposed confession was delivered by an imitator; it is not authenticated testimony about Ursula. Frightened, Ursula takes Bela out of the house. Russ also searches the house, and the family begins staying with others.

They find temporary shelter with friends Amanda and Dan and then Grandma Ruth. An apparent sighting at the friends' home makes Amanda and Dan afraid to keep the family there. Grandma listens to Bela and urges her parents to seek help. Lois Anthony, a woman interested in unusual phenomena, interprets the figure's demand as possible possession but does not know its nature. At an attempted group intervention, Kyle claims Other Mommy has given Bela a present. Ursula soon reports that Frank Doherty has died in a closet. Bela suspects his death might be the present, but the cause and any connection to Other Mommy are not established. The family briefly stays in Frank's house, which Ursula knows well, creating further tension between the parents.

After unsuccessfully seeking help in Goblin, they take refuge with Grandma's friend Evelyn. The adults briefly enjoy drinking and dancing, but Other Mommy appears to Bela in Evelyn's bathroom while the parents are sleeping. Evelyn also sees a frightening figure, orders the family to leave and refuses to go with them. Deciding that travel has failed to protect them, Ursula and Russ return home, install alarms and cameras, obtain trained guard dogs and keep Bela close. Bela remembers that Other Mommy once imitated the babysitter Kelvin's voice. Later a figure appearing as Kelvin offers to repair the parents' strained relationship if allowed to become Bela for a day. Russ calls the real Kelvin, who is not in their house.

Russ hires Brian, a self-described investigator who says he can trick the figure. When Other Mommy appears in the dining room, its extended mouth and a forceful wind frighten the family. Brian touches it and then reveals that this direct experience was all he had wanted. Rather than helping, he abandons the family and strikes Russ in an altercation outside. Ursula and Russ decide to attack the entity themselves. They arm themselves with kitchen knives, find a voice coming from an upstairs storage closet and stab toward it. They cannot locate the figure when the light comes on. Before they can continue, Lois returns and suggests that Other Mommy is attracted to Bela's innocence. Lois proposes removing that innocence through a painful disclosure. The theory is not verified, but the parents agree to hear it after their other attempts have failed.

Lois takes the family to a beach on Lake Michigan, hoping greater distance and open space will reduce the encounters. There, Ursula tells Bela about her previous marriage to Douglas Cain, her affair with Russ during that marriage and her pregnancy. Ursula says a paternity test showed that Russ was not Bela's biological father and identifies Douglas as the father. She also explains that after Douglas left, Russ chose to raise Bela as his daughter. The revelation destroys Bela's confidence in what her parents have told her. Believing she can see Other Mommy on the beach, she begins deliberately telling the adults that the figure is gone. The next day Bela runs into the water in distress and describes seeing the figure below the surface. The adults pull her out. When Lois asks whether they saw anything, Ursula slaps her, and Lois leaves.

On the drive home Ursula speculates that the frightening experiences are retribution for the way she has treated her family. Russ disputes this explanation. Bela hears and feels possible movement near the car's trunk, but cannot identify its source. Grandma Ruth meets them at their home and confirms to Bela that she is still her grandmother. Ruth describes the heart as a house with room for many feelings and urges Bela not to let her justified anger over the hidden parentage become permanently fixed. While Ursula and Russ sleep nearby, Ruth and Bela work on a Michigan puzzle.

Growing drowsy, Bela sees Grandma seeming to change position and appearance between blinks. The apparent grandmother repeats the familiar question about inviting someone into Bela's heart. Bela flees into the foyer closet and finds the real Ruth there, her eyes closed and hands folded. From upstairs she hears Grandma's cries, growling and heavy impacts as her parents rush toward the noises. After the house falls quiet, Bela discovers Ursula and Russ lying face-down on her bedroom floor. Their condition is not confirmed. Other Mommy appears and again asks to enter Bela's heart. Thinking of her parents' happiness and wanting a friend, Bela agrees. She then describes Other Mommy taking her place on the bed while she enters an immense space that is neither a closet nor a home. She hears her own voice introducing itself as Bela. The ending portrays the apparent exchange from Bela's perspective without establishing whether the adults are dead or whether the displacement can be reversed.