In a forest outside the small town of Baztan in Spain, there’s the dead body of a young girl.
Among the trees, a shadow watches from afar. Soon the police arrive with Inspector Amaia and begin
looking for clues. The girl disappeared last night after losing her bus, and her shoes have been
left next to the road. The body shows she’s been strangled with a rope, all her make-up was washed
up, there are various animal hairs mixed with hers, and there’s a traditional sweet covering
her groin, which has been shaved. There are no signs of abuse, but the position of her hands
isn’t natural. Nearby they find her bag with an ID: her name was Ainhoa and she was only thirteen.
All this sounds familiar to Amaia, so she goes to prison to interrogate the boyfriend of Carla,
who was killed a month and a half ago. The guy explains that Carla liked it rough and that he
never wanted to leave her alone on the road, but it was her who refused to ride with him
that night. Crying, he swears he didn’t do it, and Amaia believes him. Later at the police station,
the test results come back and confirm Amaia's theory: Carla and Ainhoa were killed by the same
rope, so they’re facing a serial killer. Since Amaia used to work for the FBI, she’s assigned
to lead the case. This means she’ll have to stay in Baztan, which happens to be her hometown. When
she arrives at Baztan, she immediately goes to the police station to meet the local cops and continue
making the comparison between Carla and Ainhoa. Both girls had a sweet on their groins and animal
hair mixed with theirs. Afterward Amaia goes to stay at her childhood home with her aunt Engrasi
and her sister Rosaura. Being here again brings back memories of her childhood and how her mother
Rosario used to ignore her or push her away. The next day Amaia and Officer Jonan go to Ainhoa’s
funeral and see someone suspiciously sneaking around. They chase after the man and discover
it’s Rosaura’s husband Freddy. He claims he ran because Amaia’s presence makes him nervous since
he and Rosaura had a fight and that’s why she’s been staying at her aunt’s. They’re suddenly
interrupted by Victor, the ex-husband of Amaia’s other sister Flora. Although they’re separated,
he still occasionally talks to her. Later Amaia goes to see Flora, who has taken over the family’s
commercial bakery and has always resented her sister. When Amaia reveals the sweet from the
crime scene, Flora tastes it and determines that it was made with fresh top-quality ingredients in
a wood-fired oven. Only a few shops make such great quality, so Flora will have a list ready
for the next day. Then Amaia returns to town and suddenly hears a mother screaming in the streets,
searching for her daughter Anne who has missed school. Amaia calls the station and they lead a
search through the forest with all the neighbors. While looking around, the cops joke about the
animal hair on the bodies, saying the killer could’ve been the creature known as Basajaún.
At that moment someone yells about a discovery, but it’s just a pair of shoes. After she orders
the officers to reinforce the search, Amaia goes home and is surprised to find her boyfriend James,
who has come to show his support. He’s heard people on the news blaming everything on Basajaún
and since he’s American, he doesn’t know what that is. Rosaura explains is a tall hairy humanoid
creature similar in appearance to Big Foot, but she’s offended that people accuse him of killing
because the Basajaún is the protector of the forest. When they go to bed, James asks Amaia why,
as a kid, she lived there with her aunt instead of with her family. Amaia avoids the question but
another painful memory comes to her mind: one day Rosario started to cut her hair rather carelessly,
and she was so forceful that the scissors made Amaia bleed. All these memories make it hard
for Amaia to sleep, so she goes to the window to watch the rain and is shocked to see Anne
standing on the bridge. Amaia immediately runs outside, but when she reaches the bridge the girl
is already gone. She quickly calls patrols to search the town to no avail. The next day Amaia
has breakfast with Jonan to discuss the next few things they’ll have to research for clues. When
they’re about to leave, they're shocked to see Flora with Detective Montes, who nobody has seen
at the station in days. Meanwhile a man on a bike finds another pair of shoes by the road. Soon the
police surround the area and find Anne’s body in exactly the same condition as the last girl,
sweet included. The doctor believes she’s been dead for around twenty-four hours, meaning it
couldn’t have been her outside Amaia’s window. Suddenly Montes shouts because he’s seen something
moving in the woods and he fires his gun, but only to hurt a pregnant coipo otter. Montes swears he
saw a humanoid shape, and since his bullet hurt the babies, Amaia shoots the poor mother for
mercy. Later Jonas and Amaia go to talk to Anne’s parents. Amaia checks the girls’ room and finds
the red coat she saw her in the other night with a pocket full of walnuts. Then she checks Anne’s
computer and discovers a folder with lots of suggestive pictures, even though the parents
said she didn’t have a boyfriend. Afterward Amaia oversees the autopsy, confirming this girl had the
hands in the same position and her make-up was removed. She thinks the killer has a ritual to
purify the girls and compares the hand position to an image of the Virgin Mary, pointing out that all
the girls were also found by the river which could equal washing away their sins. In the afternoon,
Jonan and Amaia go to Anne’s school to talk to her friends. A girl says Anne put up an image of an
innocent gal to trick people, but actually she had been seeing a married man in secret. When Amaia
returns home, she accidentally drops one of the walnuts, and Engrasi explains walnuts symbolize
the power of witches. Then Amaia goes to her room and finds a key pendant that triggers another
memory. After the horrible haircut, her mother had also made her wear ugly clothes and Amaia
felt awful. To make her feel better, her dad gave her some money. Amaia was worried her mother would
take the money from her, so her dad also gave her an employee key for Amaia to hide the money in the
family bakery. In the evening, Rosario went to Amaia’s room just to taunt her and left a walnut
on her bedside table. In the present, suddenly Amaia wakes up and realizes she visited the bakery
without even thinking about it. She immediately rushes home and throws the key away. The next day,
Amaia and Jonan speak with a former commissioner, who remembers the case of a foreign girl who was
found dead with candy on her legs. The girl’s name had been Teresa, and she had also been
strangled and left near the river. Teresa’s hair had been perfect even though she had been dragged
through the forest, and a few months later they found another girl with perfect hair by the river
too. More girls with perfect hair kept showing up in different areas and the man offers a map,
but he admits they never found any clues or suspects. Afterward Amaia goes to the bakery and
sees Flora arguing with Victor. When Amaia goes inside, Flora gives her the list she prepared,
but Amaia also asks for a sample of flour. Then Amaia leaves and finds Victor outside,
but their chat is interrupted when she gets a shocking call. Amaia rushes to Freddy’s house
but he won’t answer the door so she checks the window, only to discover he’s tried to
self-delete. A desperate Amaia breaks down the door and runs to cut the rope to save him, and
once he’s safe on the floor, Amaia finds a note in his injured hand that says "I love you, Anne.
I will love you forever". Later at the hospital, a doctor confirms it was a self-deletion attempt and
the wound on Freddy’s hand wasn’t defensive. Amaia shows Rosaura the note and Rosaura explains she
had known Freddy was cheating on her, but not with whom. She thinks that Freddy is lazy and useless,
but not a murderer. Since Freddy can’t talk, Amaia goes to see a friend of his, who ignores her until
he hears that Freddy could be a suspect. The friend confirms he was with Freddy the night of
the murder because he took him to a bar. Freddy had been behaving very weirdly and kept calling
a woman who ignored him, and Freddy became so angry that he punched a mirror and hurt his hand,
so they went to the hospital for stitches. The next day Amaia goes to Anne’s funeral and she’s
shocked to see Flora there. Amaia is suddenly taken away by a police officer because another
dead girl has been found, although this time the body is in an abandoned house in the woods. Her
name was Johana, she was fifteen, and she ran from home often, so the mother hadn’t reported
her disappearance. The doctor thinks she’s been dead for about a week. The body is missing an arm,
her face is full of bruises, and an injury on her neck indicates she was strangled by hand.
There’s no sweet on her groin and she was abused, so they think someone saw the news and is making
a bad copy of it to blame the crime on the serial killer. At that moment Amaia looks out the window
and sees a shadow moving among the trees so she runs outside, but finds nothing. When they return
to the station, Johana's mother shows up to tell them her daughter was killed by her husband Jason.
Johanna is the child from a previous marriage, and when she married Jason, at first he was a
good stepfather. But when Johanna grew up, he started seeing her with new eyes and he became
obsessed to the point he put a tracker in her phone. The day Johanna disappeared, Jason told
his wife that he had taken the tracker out, which couldn’t be a coincidence. While the officers go
looking for that man, Amaia meets with Jonan, who has the results of his research. He's found
seven more cases with similar characteristics, but none of them had arrests. Back then nobody
suspected they could’ve been done by the same person because there were a few differences, but
Amaia and Jonan can tell this is someone who has been testing a ritual until he found the perfect
combination. The first case had been Teresa, the body with the candies from fourteen years
ago. During those years, the killer had been more violent, and Jonan thinks he was trying to punish
the girls who were into debauchery as a service to society. However after a bunch of deaths,
there was a seven-year period with no victims. His return wasn’t Carla but a girl last year that
everyone had thought fell off a cliff. Her hair had been perfectly combed and the hand position
matched Virgin Mary’s. Amaia and Jonan conclude that the killer is making a show out of the deaths
because he wants his message to reach all the locals. Since the girls from a decade ago were
from different towns, Amaia wants Jonan to check the newspapers from the days of their murders
to see what linked all those towns because she doesn’t think the killer chose the destinations
at random. That night, Amaia allows Engrasi to do a tarot reading for her. The cards say that the
killer is nearby and that he’s coming after Amaia and her family. When Amaia asks for his identity,
the card of the Devil comes out and Engrasi cries out in fear. Meanwhile by the road, a girl misses
the last bus, but soon a van appears and takes her away. It even drives past a police car,
which doesn’t notice anything. The next day, Johanna’s stepfather Jason is found unconscious
on a trail. Amaia goes to interrogate him and he immediately admits he beat up and abused Johanna
before killing her. To try to hide his crime, he tried to make it look like what he had seen
on the news. However Jason denies having cut the girl’s arm and says someone moved him to the trail
last night because when he fell asleep he had been in the forest. He even has a blurry memory
of someone carrying him. Before Amaia leaves, a ranger tells her that he heard a whistle in
the woods and when he tried to follow it, he saw a humanoid shadow taking a bag into a cave. He tried
to approach the person for an interrogation, but when the ranger got close enough,
the person had already disappeared. Moments later, Amaia arrives home to discover they’re
having a family dinner. An argument is already going on because Flora thinks dying doesn’t make
those girls saints and she disapproves of their debauchery, but when Amaia starts to argue back,
Engrasi tells everyone to drop the subject. However Flora keeps complaining, mentioning how
Amaia left the town instead of helping her sisters take care of their sick mother. She regrets having
sent Rosario to a clinic and James is shocked to hear this because Amaia had told him her mother
was dead. When Amaia says in her mind Rosario is indeed dead, Flora insults her and leaves with
Victor. At that moment Amaia gets a call from the station and rushes there to learn that none
of the flour samples match the sweets from the crime scenes. There’s only one sample left that
they haven’t analyzed yet because it came later, and Amaia worries because it’s the one belonging
to Rosaura. Suddenly she and Jonan see Montes enter the station, which is weird because today's
his day off. They check the security cameras and discover he’s grabbing some reports before heading
out. The duo follows Montes to a cafe where he meets Flora and gives her the reports, so
they immediately rush inside to point out this is stealing evidence. Flora refuses to say anything,
so Jonan arrests her. When they return to the station, Amaia grabs the latest report and reveals
that Flora gave them a different flour from the one that she actually uses. She knows this because
Rosaura uses the same flour yet the test results are different. Rosaura’s flour matches the crime
sweets, so Flora cracks and admits she changed the flour to protect her business. Many of her
employees take flour home and she didn’t want to get involved. An argument ensues, only to be
interrupted by Amaia’s boss, who calls her to his office. The boss has discovered that Freddy had a
relationship with Anne and learned about Flora’s flour trick which Amaia had been hiding from the
other cops. He decides this is a conflict of interest and takes Amaia out of the case,
giving it to Montes instead. Amaia tries to tell him that Montes and Flora are working together,
but the boss believes Montes’ story that he had only been interrogating Flora as a suspect. On
her way out, Amaia sees everyone running to find another girl who just disappeared. Moments later
Amaia gets a call from her mentor in the FBI, who reminds her to go back to her origins to remove
the trauma that blocks her vision. Amaia goes to the bakery and remembers the night that she used
her father’s key to hide the money. Suddenly Rosario arrived, so Amaia tried hiding under
the furniture. Her mom found her anyway, and when she saw the money and the key, she accused
her of stealing from her own family. Amaia tried running away, but Rosario grabbed her and slapped
her multiple times. When Amaia managed to push her away, Rosario went crazy and grabbed a rolling pin
to hit her with it. Later Rosario went home in a dazed state and when her husband saw the key,
he desperately rushed to the bakery. To his shock, he found an unconscious Amaia buried
in the flour cask. The father immediately saved her and took her to the hospital,
where the doctor explained the flour created a scab that saved her from bleeding out, he also
mentioned that Rosario kept on hitting Amaia after she fainted. Once Amaia was discharged,
her father sent her to live with Engrasi. Back in the present, Amaia decides to go see her mother at
the clinic. She finds her tied to the bed and asks her if she has anything to do with the murders,
but Rosario insults her and tries to attack her, so an upset Amaia leaves. On her way out,
a doctor explains they had to tie Rosario because she attacked a nurse and ate the flesh she tore
off while repeating Amaia’s name. The doctor then reveals her brother-in-law comes to see Rosario
very often and even brings her flowers. Meanwhile Jonan is researching the old newspapers and finds
Flora in a picture. Then he keeps looking and sees Victor appearing in a bunch of motorcycle
conventions. He's the brother-in-law the doctor meant, not Freddy. Amaia calls him with the same
conclusion, so she tells him to inform the others while she goes after Victor. Unfortunately Montes
doesn’t get the call because he’s exploring the cave the ranger saw and he has no signal. Back to
Amaia, she’s speeding under the rain and finds the road blocked, so when she tries to hit the brakes,
the car skids and rolls down the hill, landing upside down. At the same time Jonan arrives at
Victor's house, only to find it empty. He tries calling Amaia to tell her, but she’s unconscious
inside the car. In the meantime, Montes and his men go deep into the cave and they find numerous
remains of human bones, including children’s and a severed woman's arm. Somewhere else, Victor starts
brushing his latest victim’s hair to get her ready for the ritual. Moments later, Amaia wakes up when
she hears a loud whistle. Somehow she’s out of the car and when she turns around, she sees the
Basajaun in the fog. By following him, she gets out of the forest and reaches a mysterious house.
With her gun out, Amaia goes inside and hears a song her parents loved, noticing the oven on with
a sweet inside. She also hears a girl screaming, so she starts searching the house and eventually
comes across a collection of newspaper clippings talking about all the murders and pictures of the
girls. Suddenly Amaia is attacked by Victor, who hurts her arm with a rolling pin. When she asks
him about the girl, Victor begins ranting about how girls nowadays are all tarts that
like playing with men so he had to teach them the purity that Flora and Rosario preached. As
soon as he gets distracted, Amaia grabs some scissors and stabs his leg before running out,
kicking Victor away when he tries to stop her. When Amaia reaches the stairs, Victor catches
up to her and hits her with the rolling pin again. Amaia defends herself and a fight ensues,
during which Victor tries to strangle her. Amaia struggles and manages to push the scissor further
into his leg before pushing him away. Then Amaia runs to finally find the girl and starts to untie
her as Victor comes closer, but before he can attack, he’s shot twice by Flora. Sometime later
at the station, Amain explains the whole case. Victor killed his first victim fourteen years ago
because he considered Teresa’s foreign lifestyle a threat to the traditional town. Afterward the
guilt made him an alcoholic, which helped him convince himself he was helping society. The
next six years he killed eight more girls, but then he met Flora, who kept his anger down.
During their seven years of marriage, he didn’t kill anyone, but after their divorce Victor’s
anger came back out and he started killing again, staging everything with specific details to get
his message known and regain his wife’s respect. Then Montes adds that some of the bones in the
cave were from Victor’s victims, but other bones seemed to be from unrelated crimes. The amputated
arm was indeed Johanna’s, but it wasn’t cut by her stepfather or Victor. A few weeks later,
Flora publishes a book about the family business and calls her mother the true guardian of the
town’s purity. Meanwhile Amaia and James inform Rosaura and Engrasi that they’re having a baby.