Around ten years ago, a priest traveled to an island in Malaysia with his daughter and wife on
a mission to bring the word of god to the natives. At first they were very welcome and the island's
habitants would go to the newly built church every day. However soon the followers of the local gods
became angry that a white man was trying to overwrite their beliefs and shortly after weird
symbols and masks began appearing around, the church was burned down. In the present, American
teenager Toby ignores his father David's request to work on the car together to remember the old
times because Toby would rather fool around on his phone. David decides to work alone anyway,
and soon after he steps outside, he's surrounded by a group of masked criminals that attack him
with a knife before escaping with the car. Because the television is on, Toby doesn't hear anything
until the car takes off, and by the time he goes outside, it's too late. David's murder appears all
over the news and Toby can't shake off all the guilt he feels. His mother takes him to see a
psychologist who recommends a special program that takes traumatized people to an uninhabited island
to give them time to think and go through serious introspection, and Toby accepts. A few weeks
later, Toby's on a boat to the island, throwing up because of seasickness. This makes him the perfect
target for a prank in which he's hit by the sail and thrown into the water. After a whole day of
sailing, leader Kay explains each group member will be dropped on a different island, and they'll
have to stay there for three days and three nights. They're given a sleeping bag, a tarp,
a torch light, some food, and a flare they must use in case of emergencies. The next morning, Kay
drops Toby off and reminds him to be on the shore at the crack of dawn in three days. Seeing her
leave reminds Toby of the night the police took his father's body, but then he forces himself to
get started. He begins by making a very bad tent with the tarp while talking to himself to feel
less lonely, then he enters the jungle to pick up some wood. There are some coconuts on the ground
that he tries to grab as well, but when he moves the vegetation away, he's shocked to find a dead
monkey that reminds him of how he found David's body. He decides to return to his tent without
the coconuts, only to discover another monkey has eaten half of his food. Then he tries to start a
fire, but he fails and only manages to hurt his hand. Afterward, Toby walks into the water to see
if he can catch some fish. He ends up accidentally stepping on some shells and hurting his foot,
but at least he also finds some clams. His foot bleeds in the water and this blood reaches one
of those mysterious masks at the bottom of the sea. Later, Toby uses his swiss knife to open the
clams and discovers it comes with a magnifying glass which allows him to finally start a fire.
When night falls, Toby has the clams for dinner, but they make him feel sick. After throwing up,
Toby walks into the jungle with the torch light to look for those coconuts in order to have a drink,
but when he finally finds them, he hears someone running behind him among the trees. By shaking his
torchlight around, Toby finally gets to see that the source of that noise is a creepy face behind a
tree that suddenly runs off. Terrified, Toby runs back to his camp and lights the flare before he
passes out as memories of his father's death flood his mind. During the night, the high tide takes
most of Toby's things away. The next morning, Toby mysteriously wakes up resting against a tree,
and there are already cut coconuts waiting for him. After having a good drink, Toby's shocked
to notice there's a girl in the water, and when she tries to leave, he follows her. The girl
suddenly turns around with a knife in hand, but it turns out she doesn't want to attack Toby, she's
just following the sound of an animal trapped in one of her many traps. Madeleine explains
they can't stay there because it's dangerous, so Toby follows her after noticing exactly how deadly
those traps are. He has lots of questions for Madeleine, but she doesn't talk except to share
her name. They make it to a damn that was built by missionaries, and Madeleine starts a fire to cook
her catch and share it with Toby. When they're done, Madeleine announces she's going home and
that Toby can't follow her. Toby tries to anyway, and Madeleine suddenly takes her knife out again,
but it's to kill a snake that almost kills Toby. Before leaving for good, she advises
him to stay close to the fire because it keeps the animals away, and Toby follows her instructions,
falling asleep inside a makeshift shelter that was already on the damn. That night, one of his
dad's killers finds Toby and attacks him, but it turns out to be just a nightmare. Now awake,
Toby notices the fire's out and tries to start a new one, getting nervous as he keeps hearing
noises in the darkness. Thinking it may be Madeleine, Toby enters the jungle and finds
some thread that shakes some weird decorations on a tree when he pulls it. The creepy figure appears
behind Toby and tries to come closer, but as soon as Toby turns around, the creature is gone. The
next morning, Toby wakes up in the shelter to find Madeleine already cooking breakfast. She notices
the wound on his foot and takes him with her to find a special plant that will help with it, she
also shares she's been on this island since she was a child and it's only her and her mother left
because her dad died. When they find the plant, Madeleine applies it to Toby's wound, explaining
you can't eat it unless you want to fall asleep. When she puts a bit of it on Toby's lip to prove
her point, Toby realizes his lip's now numb. The teens spend the day together, and Madeleine
teaches Toby all she knows about surviving on the island, from fishing to making a shelter.
In return, Toby tells her about things like high-fives and the internet. When night falls,
Madeleine has to leave again, and Toby notices she's going in the direction of the tree with the
weird decorations. Madeleine leaves him a spear she made so he can protect himself and explains
that if he comes with her, her mother will kill him. She promises they can see each other again in
the morning, but Toby explains they'll pick him up at dawn and this hurts Madeleine, who feels she's
being abandoned. Madeleine runs to her home in the tree and Toby stays behind to try to talk to her,
so when Kay arrives at the beach at dawn, she doesn't see the boy anywhere. Kay could hear
Toby yelling Madeleine's name and enters the jungle with her torchlight out to find him,
but when she begins hearing weird noises among the trees, she trips and falls, losing the torchlight
in the process. Suddenly, Kay finds herself blinded by her own torchlight, but when she comes
closer to see if it's Toby, the light goes out and the torchlight is thrown on the ground. When Kay
reaches out to grab it, she notices two glowing eyes in the dark and without notice, a paw appears
on top of her hand. For a few minutes, the only noise in the dark is Kay's screaming. The next
morning, Toby wakes up realizing he fell asleep while calling out for Madeleine so he must rush
to the beach, but he finds it empty. He sits to wait just in case anyway, and after a few hours,
he notices a lifebuoy floating around. When he enters the water, he finds a whole trail
of objects, and he follows it to find Kay's boat floating upside down. To his surprise,
Madeleine's mother is swimming out of it with Kay's supplies. Once the woman is out of sight,
Toby swims inside the boat to investigate and finds two flares inside a cabinet, but to his
dismay, he finds also Kay's body behind a door. Terrified, Toby begins swimming away before he
runs out of air, only to get his clothes stuck on another door. Fortunately he manages to untangle
them and return to the surface just in time. Afterward, Toby enters the jungle and finds Kay's
torchlight with a weird scratching mark on it. Using this torchlight, he decides to go through
the entrance of Madeleine's tree and discovers a rocky tunnel filled with bats and weird noises.
The creepy creature approaches him from behind again and makes Toby drop the torchlight, leaving
him in darkness. The noises begin getting closer, so Toby searches the ground until he finds the
torchlight and turns it on again, which allows him to suddenly see some really creepy drawings on the
walls. Moments later, Toby finds the end of the tunnel and comes out to find what is left of the
old burned church. He also hears a goat bleating, and when he goes to check, he finds Madeleine's
mother killing it for food. Then he keeps looking around and finds the cabin where both women live.
Inside, he finds Kay's empty bag, a box with three passports, and an old picture that indicates
Madeleine and her mother are the family that came with the priest all those years ago. There's also
a can of gasoline, and most importantly Kay's radio, which Toby immediately uses to call for
help. He only gets one hello from the other end before the line goes dead, and at that moment,
Toby has to run and hide under the bed because Madeleine and her mom are back. While the mother
prepares a special concoction with the dumbing plant, she has an argument with Madeleine because
she thinks her daughter isn't ready to go out there. When Toby moves further under the bed
not to be seen, he's shocked to find an extremely creepy mask and realizes this is the face of the
creature that attacked him before. As soon as the mother leaves the room, Toby approaches Madeleine,
but Madeleine reminds him this is dangerous and promises to meet him at the beach later.
Toby makes his way back to the beach and uses everything he's learned to catch some fish and
start a fire. While having lunch, he notices a light blinking on the other end of the island and
he replies by starting an extra big fire that can be seen from a distance. In the evening,
Toby's trying to sleep when he's suddenly startled by Madeleine, who had thought Toby would be gone
by now. He explains Kay's dead and that he thinks the mother killed her, causing Madeleine to rest
her head on Toby's leg and share the few things she remembers from her childhood. She used to
be happy living with her family and playing with the local kids, but one day something happened,
and she only remembers being in a corner crying while her mother, covered in blood, told her not
to look. Madeleine admits she sees terrible things at night and that her mother probably killed them
all. Toby asks Madeleine if she wants to run away with him because they'll probably send a new boat
soon, and Madeleine accepts, but she'll come back tomorrow to avoid her mother getting suspicious.
The next morning, Toby wakes up when he hears a plane flying by, but by the time he runs after it,
it's already gone. However this run has allowed him to find an abandoned lighthouse
that he proceeds to investigate. Unfortunately the light isn't working, and when Toby checks out its
inner workings, he remembers all the things David taught him about taking care of cars,
this allows him to understand the light needs gasoline. Then Toby begins making his way
back to the beach when he suddenly bumps into someone: it's Cameron, another one of the guys
that signed up for the service. He was never picked up either, but he did find a rowboat,
so he used it to try to find other people because his own island's definitely empty. Toby shares
some food and tells him about his experience while making a new spear, which he uses to threaten
Cameron when he points out that trusting a crazy pair of murderers is dumb. After apologizing,
Toby explains he refuses to leave Madeleine behind because she's also a victim and goes looking for
her. Moments later, he makes it to the house, only to be caught by surprise by the mother.
The woman takes the spear from Toby and lets him go to try to make him see reason, but Toby runs
away. Mother runs after him and accidentally falls into one of Madeleine's traps, leaving her stuck
between a tree and a thicker spear. Knowing she doesn't have much time left, the mother explains
to Toby that she didn't kill anyone. She's only been trying to scare people away because the
crazy murderer is actually Madeleine. All those years ago, the locals tried to warn them that
something evil was on the island, but the priest didn't believe them and tried to depend on the
word of god. While he and his wife argued with the natives, Madeleine took the chance to wander and
approach the altar where the locals killed animals as an offering, this allowed the demon to use the
child as his vessel in a ritual that matched the drawings Toby saw in the tunnel. It was Madeleine
that killed everyone in the church and burned it to the ground, only leaving her beloved mother
alive. Mother then gives Toby the special plant in a bag to subdue Madeleine and points out that
she doesn't like the light when she's demonic. Before dying, mother reminds Toby that Madeleine
shouldn't leave the island. Meanwhile Cameron is waiting at the camp when he suddenly hears some
weird noises. He enters the jungle to investigate and comes across a bunch of bones on the ground
that distracts him from seeing the real danger: a demonic Madeleine appears right next to him and
drags him away through the trees to kill him. By the time Toby comes back, only Cameron's blood's
left. A noise suddenly makes him turn around and he sees demonic Madeleine coming closer with her
mother's body, but she becomes human again when she realizes Toby's a friend. She demands to
know what happened to her mother, and in order to keep her calm, Toby says he did it so they
could be together. This makes Madeleine happy and she kisses Toby, pushing him to the ground to get
frisky. Toby loses the little bag with the special plant when he falls, thus he pretends to be into
it to be able to recover it. When Madeleine notices, she growls and begins to change,
but Toby manages to find her spear and uses it to knock her out. Then, he puts the plants
in her mouth to keep her subdued and uses some vines to tie her up. Afterward, Toby runs to the
house to grab the gasoline and prepare a torch that lights his way back to the lighthouse. He
leaves the torch at the door to keep animals away then goes upstairs to finally turn on the light
while remembering the time his dad taught him how to start a car. While Madeleine begins to stir,
Toby waits for a boat, but seeing nobody is close, he decides to leave. When he makes his way down,
the stairs break, causing Toby to fall and spill the gasoline all over the floor. It also makes him
discover the special plant grows here as well. At that moment, the door closes on its own,
and as soon as the rotating light is pointing in the opposite direction, demonic Madeleine sneaks
into the shadows to attack. Toby manages to grab some of the plant before he's dragged away, but
Madeleine's too strong and when he tries to use the plant on her, she turns his hands around to
make the juice fall on his eyes instead. Madeleine then jumps away when the light comes inside again,
so Toby uses the chance to approach the sink and wash his face. Floating in the water he
finds a glass shard and when Madeleine has enough darkness to attack again, Toby uses the shard to
keep her away. Toby begins considering using the torch as well, but when he approaches the door,
he finds little Madeleine crying. He worries about the child, but this is actually a trap, and the
kid reveals her demonic face before returning to her adult form and jumping on Toby. A boat
can be heard approaching the island so Toby needs to think fast because Madeleine's in the process
of possessing him too. Toby manages to grab the shard again, and when Madeleine grabs his wrist
to stop him, Toby improvises by turning the glass enough to make the light reflect on it and burn
Madeleine's face, getting her to back away. Then Toby runs outside and grabs the torch to throw
it at the gasoline, starting a fire. Madeleine turns human again to try to be pitied, but Toby
just closes the door before running away. As soon as he makes it to the beach, Toby notices the boat
is following the direction of the lighthouse, so he gets in the water to go after it. Unfortunately
he isn't heard when he cries for help, and the noise allows demonic Madeleine to sneak behind
him and finally kill him. A few moments later, the rescuer leaves the island with Madeleine aboard,
believing her to be the person that turned on the lighthouse. As soon as the man is distracted,
Madeleine reveals she's still possessed and will cause more trouble in the city soon.