Bela says goodnight to her parents and Other Mommy emerges from the closet to greet her.

Other Mommy repeatedly asks Bela 'Can I go into your heart?' and insists that they trade places.

Mommy comes home drunk and Bela tells her she smells like another person, upsetting her.

Other Mommy appears disguised in the playground playhouse and Bela, terrified, falls backward off the jungle gym.

Bela's parents take her to the doctor, where Bela mentions Other Mommy's name and surprises them.

A guest named Marsha screams at the family's house party after seeing a tall, dark, hairy monster across the room.

Bela corrects Marsha, calmly identifying the creature Marsha saw as Other Mommy.

Bela wakes to find Other Mommy sitting on her bed, impersonating Mommy and voicing her secret regrets about motherhood.

Mommy sees Other Mommy on Bela's bed, snatches Bela up, and flees screaming into the yard.

Dan asks the family to leave his house after he believes he sees Ursula's doppelganger in his bedroom.

Ursula arrives at Lois's paranormal group meeting and announces that her lover Frank has been found dead.

The family is chased from Evelyn's house in Goblin after Other Mommy terrorizes everyone in the bathroom.

Paranormal investigator Brian sees Other Mommy floating above the carpet, then admits he only wanted the experience and leaves.

Lois returns to the house and tells the family they must strip away Bela's innocence to repel the entity.

Other Mommy asks 'Can I go into your heart?' and Bela says yes, finding herself alone in a vast empty space.

The novel opens with eight-year-old Bela casually welcoming an entity called Other Mommy from her closet as part of her nightly routine, unbeknownst to her parents. As the summer progresses, Other Mommy's demands to enter Bela's heart grow more insistent and the creature begins appearing outside the family home. Bela's parents are forced to confront the supernatural threat after guests at their house party witness Other Mommy firsthand, and the danger becomes undeniable when the creature kills Ursula's secret lover. The family turns to paranormal investigators and outside experts for help, but every adult effort fails and each would-be rescuer abandons them. When Other Mommy kills Grandma Ruth and leaves Bela's parents incapacitated, Bela is utterly alone with the entity she once called a friend. With no one left to protect her, she says yes to Other Mommy's demand and finds herself transported to a vast, empty void.

The core haunting and its devastating conclusion.

Daddo checks on Bela upstairs, notices a strange smell, and she rushes him back downstairs to hide Other Mommy.

Daddo and Bela watch three romantic comedies together while waiting for Mommy to come home from work.

Bela asks Deb how she would handle a woman in her closet, and Deb runs terrified to their mothers.

Russ introduces Bela to Lois Anthony at the party, and Lois tries to sense whether Bela has supernatural abilities.

Russ enters Bela's room after the party, tells the closet that ghosts should leave, then fixes the creaking door.

Mommy returns the morning after the party still in her party clothes, having not slept at home.

The family encounters Lois at the zoo, and she invites them to attend her paranormal group's weekly meeting.

Mommy empties Bela's closet, opens all the windows, and orders Bela to lie down for a nap.

The family drives to Grandma Ruth's house after being expelled from Dan and Amanda's home.

Grandma Ruth confronts the family and demands honest, plain answers from Bela about Other Mommy's visits.

Russ walks with Bela in the woods behind Grandma's house and warns her never to say yes to Other Mommy.

Grandma Ruth informs Russ that Ursula has quietly slipped away from the house, claiming she needed to see a friend.

The family sleeps overnight in a gas station parking lot after fleeing from Frank's empty house.

The family travels to the town of Goblin seeking supernatural expertise but fails to find any real help.

Grandma Ruth and Bela stay up working on a puzzle while Grandma tries to keep Bela awake through the night.

This pool traces the quieter but equally revealing moments of Bela's home life and the family's increasingly frantic attempts to find shelter and help. From peaceful evenings watching movies with Daddo to Bela's disturbing conversation with her friend Deb at the park, the events show how isolated and burdened Bela already is before the haunting becomes undeniable. Grandma Ruth emerges as a steady, practical counterweight to Russ and Ursula's avoidance, demanding honesty from both the adults and from Bela herself. Ursula's repeated disappearances — to her lover and then away from the family entirely — leave Russ and Bela to face the danger largely alone. The family's search for safety takes them from hotel rooms to the town of Goblin, but every refuge fails them. The pool closes on the eve of the final catastrophe, with Grandma Ruth and Bela sharing one last quiet moment over a puzzle.

The family's daily life and desperate search for safety.

Bela recalls telling her parents about Other Mommy as a young child; they teased her, so she stopped mentioning it.

After the party, a stoned Russ sits on Bela's bed and delivers a rambling monologue about adulthood, death, and fear.

Mommy asks Bela to describe Other Mommy in detail; Bela reveals the entity can change sizes and slithers on its belly.

Bela panics in the butterfly house after spotting what looks like Other Mommy's eye watching her from under a leaf.

Bela and Dan both wake during the night at Dan's house hearing noises, suggesting Other Mommy has followed the family there.

At Lois's seance, Kyle whispers to Bela that Other Mommy sent her a present, then blows out all the candles.

Bela concludes that Other Mommy killed Frank as a gift for her, hoping to stop her parents from divorcing.

Grandma Ruth and Ursula visit a church seeking help, but priests refuse and question whether the family abuses drugs.

Other Mommy impersonates Kelvin in Bela's dark bedroom and offers to fix her parents' marriage if they switch places.

The guard dogs growl at the foot of the dark staircase, alerting the family that Other Mommy has returned to the house.

Russ and Ursula arm themselves with kitchen knives and march to Bela's closet to confront Other Mommy.

At the Lake Michigan campsite, Bela and Lois watch a distant dog-shaped figure in the dunes that never draws closer.

Ursula tells Bela around the campfire that Russ is not her biological father and explains her first marriage.

Bela calls her parents liars and then lies to the adults around the fire, claiming Other Mommy has gone.

Bela finds Grandma Ruth's body hidden in the foyer closet and discovers her parents lying face down on the carpet.

This pool focuses on the hidden truths and pivotal decisions that drive the story toward its tragic ending. Early turning points — Bela's suppressed first disclosure of Other Mommy, the creature's chilling appearance in the butterfly house, and a failed seance — establish a pattern of denial and powerlessness among the adults around her. The danger escalates when Other Mommy impersonates Kelvin to manipulate Bela directly, and Russ and Ursula's desperate knife attack proves completely futile. The most devastating revelation comes at the Lake Michigan campfire, where Ursula's confession about Bela's true parentage shatters Bela's trust in every adult she loves. Stripped of her innocence and convinced that all adults are liars, Bela resolves to lie in return and stops resisting Other Mommy. The pool closes on the night Other Mommy kills Grandma Ruth and overcomes Bela's parents, leaving Bela with no one left to turn to.