The movie opens with a young mother named Sarah, and her eight-year-old son, Chris,
who have recently moved to a peaceful countryside home in Ireland.
However, this change has brought some challenges for Chris, who finds it difficult to make
friends at school, and often becomes a target for bullying by one of his classmates.
On their way back home, Sarah and Chris engage in a heartfelt conversation about their life
in the new house.
And then all of a sudden,
They encounter an unexpected obstacle on the road, and as Sarah steps out of the car to
retrieve her side mirror, she comes face to face with a mysterious old woman wearing a hood.
The woman's constant murmuring adds an eerie atmosphere to the encounter, and her strange
gaze towards Chris intensifies the situation.
Sensing something unsettling, Sarah quickly grabs the mirror and decides to leave the
unsettling scene behind.
To help Chris feel more at ease in their new town, Sarah tries her best but faces challenges
like dealing with his selective eating habits.
She tries to make mealtime enjoyable by playing their favorite game of making funny faces.
However, despite her efforts, she struggles to fill the void left by Chris's father, which
makes Chris often wonder where his father is.
One day, when a spider frightens Chris, he desperately asks Sarah to kill it to prevent
it from entering the house again.
Sarah, however, refuses his request and opts to release the spider outside instead.
This refusal angers Chris, who believes his father would have taken care of it for him.
He crushes the spider beneath his feet, and accuses Sarah of lying about his father's presence.
The boy runs away from her in his emotional outburst and disappears into the woods.
During her search for Chris in the woods, Sarah stops in her tracks when she stumbles
upon a strange sight.
It's a massive sinkhole in the ground.
Just then, Chris emerges from behind her, offering a heartfelt apology for his behavior,
and they share a tender embrace.
The son asks what hole that is, and the mother doesn’t want to stay there any longer, so
she brings her curious son back home.
The following day, Sarah hosts a dinner where her boss, Lil Jones, shares a chilling story
about the mysterious woman named Noreen who resides near Sarah's house.
It turns out that the old woman Sarah encountered earlier is Noreen.
Lil reveals that Noreen's son, James, was once a classmate of hers.
When James was eight years old, Noreen stormed into the classroom, completely crazy, and
began screaming insane things about her own son.
James was temporarily withdrawn from school, while Noreen was admitted to the hospital
for therapy.
But when she was discharged months later, tragedy struck when James was tragically crushed
under his mother's car, with uncertainty surrounding whether it was an intentional act or a terrible accident.
Sarah is already deeply disturbed after hearing the unsettling story, but her anxiety rises
to the next level when she discovers Chris missing from the house later that night.
Filled with fear, she tirelessly searches through every corner of the house, and ventures
into the darkness of the surrounding woods, desperately seeking her son.
Amid her frantic search, she catches a glimpse of someone behind a tree, which only adds
to her fear.
Summoning her courage, she investigates, but to her confusion, there's no one there.
Unable to locate Chris, she decides to return to the house and contacts the authorities
for help.
Just as she is about to report the mysterious incident, Chris suddenly reappears, claiming
he never left the house.
Sarah's concern deepens as she is confident that Chris was not present earlier.
Feeling unwell, she contacts a doctor, who asks her if she has a history of anxiety and
checks the scar on her forehead, which was caused by an accident a year ago.
After checking her, the doctor prescribes her some sedatives to take before going to bed.
One day, when she calls Chris for lunch, the son is nowhere to be found.
But then, out of nowhere, when she looks back at the table, he mysteriously appears at the
table instantly.
Moreover, despite his previous struggles in making friends, Chris has now formed a close
bond with an entire group, including the child who used to bully him.
Things start to get even weirder when Sarah and Chris unexpectedly come across Noreen
standing in the middle of the road on their way home.
As Sarah exits the car to help move her off the road, Noreen gazes at Chris and tells Sarah this....
Suddenly, Noreen's husband, Des, arrives on
the scene, apologizing for his wife's behaviour, and engaging in a neighbourly conversation with Sarah.
Seeing Noreen getting too close to her car, Sarah decides to cut the conversation short.
Here Noreen becomes uncontrollable, banging her head against the window and screaming
that Chris is not her son while Des tries to calm her.
Sarah manages to drive away that day; however, the mother still feels unsettled and disturbed
by Noreen's strange claims about Chris, so she revisits her to get answers.
To her shock, when Sarah enters the house, she finds Noreen lying dead with her head
buried in the ground and crows feeding on her lifeless body.
The police are called to investigate Noreen's tragic death.
During the process, Sarah witnesses a disturbing scene where one of the cops distracts Chris
by playing arm wrestling with him.
She suddenly sees Chris using unnatural strength to win, even breaking the officer's wrist.
Luckily, it's just a product of her anxious mind.
As the unsettling incident of Noreen's death continues to weigh heavily on her, Sarah's
forehead wound starts bleeding again, adding to her distress.
Worried about her son's strange behaviour, she decides to confide in her boss, Lil.
Sarah shares her suspicions about not recognizing her child due to changes in his behaviour.
But Lil brushes it off, relating her own experience with her twins, who can switch from being
angels to monsters and back in the blink of an eye.
Later in the day, Sarah attends Noreen's funeral, and sees her house's walls adorned with mirrors
now covered in black cloth.
Concerned about Noreen's earlier comments regarding Chris, she approaches Des and asks
him about her peculiar behaviour.
Here Des reveals that when their son, James, turned eight, Noreen became convinced that
he was no longer their real son, but an imposter inhabiting his body.
He further discloses that it was he, not Noreen, who was driving the car during the accident
that tragically claimed James' life.
The following morning, during her morning jog, Sarah discovers Chris’s toy soldier
near the sinkhole she saw earlier.
Curious, Sarah tries to approach the huge sinkhole and sees it is constantly eating
the land around it, while incomprehensible whispering can be heard from within.
Once she returns home, she feels that something is off with Chris once more, as she observes
her son willingly eating foods he always refused to eat.
As she questions Chris about the toy she found earlier, he denies going out near the sinkhole,
causing Sarah to raise her voice in frustration.
And then all of a sudden…
Chris becomes enraged and forcefully pushes
the table, displaying a mysterious strength that challenges Sarah's belief that he is her son.
When it gets dark, Sarah hears some freaky sounds coming from Chris' bedroom.
She creeps closer to his room so she can watch him through the keyhole and the crack under the door.
Here things get scarier when she witnesses Chris moving around the room on all fours.
He also catches a spider,
and proceeds to eat it, even though he used to be afraid of it.
Troubled by these changes, she decides to consult a doctor, only to find that Chris
appears to be physically fine.
Instead, the doctor suggests that Sarah's own well-being might be questioned, pointing
to her scar and the incident that might have affected her a year ago.
Worried about her sanity, Sarah purchases a camera, and discreetly places it in Chris's
room, hoping to uncover the truth about her son's behaviour.
The next day, she apologizes to Chris for her recent odd behaviour.
All of a sudden, Chris responds by touching her forehead, and violently scraping her wound.
Thankfully, it was all just a nightmare, and Sarah was physically unharmed, but her mental
state is still questionable.
Later that day, she attends her son's school performance, but something strange happens.
The entire crowd in the auditorium vanishes, and Chris's gaze becomes fixed on her.
His voice deepens, and his eyes reveal a chilling truth.
Overwhelmed with fear, Sarah panics and flees from the hall.
She then encounters Chris's teacher, and when the teacher inquires as to her well-being,
Sarah repeatedly asserts that Chris is not her son.
Chris appears and asks if his mother is alright, so Sarah runs away from the school, and rushes
to review the camera footage.
Shaken by the revelations in the video, she decides to visit Des in search of answers
to her concerns.
There, she discovers why Noreen had so many mirrors in her house.
Even after James' death, Noreen would use the mirrors to check if Des was alright, or
if he was turning into someone like James.
She would examine Des daily to ensure he was her real husband.
When Sarah tries to share her concerns with Des about Chris facing a similar situation,
he becomes furious and refuses to watch more footage.
Des knocks the camera to the floor and refuses to believe anything about his son and wife.
Before leaving, Sarah urges him to call her crazy or dismiss her claims, but Des hesitates
to do so.
Later that day, as Sarah is retrieving the memory card from the broken camera, Chris
joins her, questioning why she left him at school.
She quickly fabricates an excuse about her health, and in an eerie tone, he tells Sarah
that he doesn’t like being left alone.
After an uncomfortable hug with Chris, Sarah begins preparing for dinner.
While she is in the kitchen, we see her sleeping pills in the trash bin, which kinda suggests
that she's sneaking them into Chris' food.
Nevertheless, during dinner, Sarah can't ignore the fact that Chris is eating something he
used to dislike.
To test if Chris is truly her son, she initiates a game they used to play together.
Yet again, instead of making the expected funny face, Chris remains unresponsive, which
makes Sarah even more sure that he is not her son.
It is at this point that the entity realizes its game is up.
When the mother awakens, she finds herself
being dragged by Chris towards the garden, where he intends to bury her alive, mirroring
what happened to Noreen.
Luckily, as Chris covers Sarah's head with mud, the sleeping pills take effect at that
point, and the creature passes out.
As Sarah does not get covered with too much dirt, she manages to free her head from the
hole and escape further danger.
Taking advantage of Chris's unconscious state, she carries his body to the basement and uses
the car's side-view mirror to validate her suspicions.
To her horror, she witnesses a bizarre creature in the reflection, confirming that a shapeshifter
has indeed taken over Chris's body.
As the imposter regains consciousness, he launches a violent attack on Sarah.
However, being in a child's body, he is overpowered easily.
Despite her fear, Sarah manages to subdue him, and locks him in the basement while his
screams echo through the air.
Determined to find her real son, Sarah heads to the sinkhole, suspecting he may be there.
But then, as she descends, the hole engulfs her, hurling her into an underground tunnel.
Navigating through the dark, she overcomes obstacles and moves from one tunnel to another,
until she finally reaches a cavern.
In the eerie surrounding, she discovers a scattering of skeletons, but, to her relief,
she also finds Chris covered in dirt and branches.
Before she can wake him, a chilling growl echoes through the cavern, coming from a horde
of faceless creatures.
Facing an army of shapeshifters, Sarah is left to fend for herself and drag Chris all
the way back up to the sinkhole.
As she crawls through the narrow tunnel, she is pursued by one of the creatures.
Upon reaching the other end of the tunnel, a shapeshifter grabs her leg and takes on
her appearance, shocking her.
Sarah relentlessly beats the creature with a torch, until she finally manages to defeat
it and escape the sinkhole.
Once they are out of the hole, she tries to wake Chris, and is relieved to find him still
alive.
Eager to leave the eerie place behind, she takes Chris back to her house.
Unfortunately, the car is locked, forcing her to enter the house to retrieve the keys.
After leaving Chris next to the vehicle, she enters the living area but is interrupted
by the imposter, pleading with her in Chris's voice to be released.
Determined not to give the imposter another
chance to deceive her, Sarah ignores the pleas, sets the house on fire, and leaves the area
forever with her real son.
Months pass, and Sarah and Chris return to a normal life.
However, the disturbing experience still stays in Sarah's mind.
To reassure herself that she is truly living with her real son and not an imposter, she
hangs many mirrors around the house just like Noreen and regularly takes photographs of Chris.