Walking home through the rain, Rosalina anticipates the mess her father left in their house during his brief visit before he left for the Briarwood Forest to continue his search for his missing wife. Rosalina worries about his safety but knows nothing will stop him in his quest.

Passing the Poussin Hunting Lodge, Rosalina avoids the building because of the painful memories it holds of her break-up with Lucas. She walks past an abandoned building that she dreams of converting into a library. She reflects on giving her college fund to her father to save their house from foreclosure and fund a trip to Scotland, sacrificing her own future.

Near her mother’s favorite weeping willow tree, Rosalina discovers the free little library she set up has been destroyed with graffiti slandering her father’s belief in faeries. As she kneels among the ruined books, a truck with the Poussin Hunting Company logo pulls up and crushes the library’s remains under its tires.

The driver is Lucas Poussin, Rosalina’s ex-boyfriend. He’s well-groomed and confident, making Rosalina painfully aware of her muddy, disheveled appearance. Lucas tells her that he graduated with honors from university but quit his job at a city accounting firm where he was briefly employed. He grips her chin and calls her beautiful, ordering her to meet him for dinner at the lodge the following evening. He mocks her father’s faerie-hunting, then drives away, leaving her alone with her destroyed library.

The next evening, Rosalina arrives at the Poussin Hunting Lodge to find that Lucas has thrown a party for the entire town. She feels underdressed and out of place among the crowd. Lucas finds her on the upper level and speaks to her condescendingly, calling her his innocent Pumpkin and offering her a front desk job at the Lodge. When he pulls up her left sleeve, revealing a scar, her past with him resurfaces.

In a flashback eight years prior, before leaving for university, Lucas carved his name into Rosalina’s forearm with his hunting knife to ensure she would remember him. In the present, Lucas admits he had forgotten about the scar but says now that he is home, she need not worry.

He kisses and gropes her, then pulls her down to the main floor. Lucas jumps onto a table and announces to the crowd that he is taking over management of the family lodge. He declares he’s officially off the market and gets on one knee before Rosalina, proposing with a large diamond ring. Rosalina is shocked into silence, unable to answer.

Before she can respond, Thomas, the butcher’s son, bursts into the lodge. He explains he got lost while hunting and found George’s jacket covered in dried blood. Ignoring Lucas’s proposal, Rosalina tells Thomas to take her to where he found the jacket, determined to rescue her father.

At night in Castletree, located in the Enchanted Vale, Keldarion hears a human voice echoing through the castle. The presence of a human intruder indicates the castle’s magic is weakening. With the other princes away, Keldarion resolves to handle the situation himself. He stalks to the great hall in the form of a huge wolf-like beast, frightening the servants.

He discovers a tall, aging, human man, soaked from the rain and carrying a sack. The man, George O’Connell, says he was chased by goblins and is searching for his wife. A servant named Marigold suggests offering help, but Keldarion refuses. George notices a rose growing in the thorns by the fireplace and plucks it, saying it is a gift for his daughter, but Keldarion’s rage erupts.

Abandoning any thought of mercy, Keldarion reveals himself as the master of the castle and calls George a trespasser and thief. George pleads for help, explaining he has searched for this realm for 25 years. Keldarion steps into the light, revealing his terrifying beast form. He notices a moonstone rose locket around George’s neck. Despite George’s pleas, Keldarion declares he will remain a prisoner for eternity and drags him to the dungeon.

That same night, Rosalina, Lucas, and Thomas search the Briarwood Forest for her father. Rosalina has them turn off their flashlights to follow a distant flickering light. She discovers a massive rosebush blooming out of season, its thorns stained with blood and torn fabric. Thomas confirms this is where he found George’s coat. Rosalina determines that her father went through the bush and begins crawling through the thorns. Lucas sends Thomas home and follows her.

They emerge into a strange, dark realm filled with massive purple-black briars beneath a night sky. Rosalina realizes they have entered the Enchanted Vale, confirming her father’s stories about the land of the fae are true. Lucas unstraps his rifle as they follow a narrow trail, keeping the red rosebush portal in sight behind them. Rosalina calls out for her father.

Strange chittering sounds surround them, and grotesque humanoid creatures with ashen skin, yellow eyes, rotting flesh, and sharpened thorn blades emerge from the mist. They are accompanied by diseased, hyena-like beasts.

Two of the creatures, Launak and Aldgog, identify themselves as goblins and call Rosalina and Lucas lost humans. The goblins chant menacingly as they close in. When Rosalina asks about her father, they confirm they saw an old man who was taken by Winter—Keldarion and his beasts. The goblins grow fearful as they mention Keldarion’s name.

Lucas opens fire with his rifle, killing several goblins. He and Rosalina run as the survivors give chase. Lucas falls and loses his rifle under a thicket. One of the hyena creatures attacks him, and Rosalina stabs it with a large thorn, allowing Lucas to push it into a gully. They sprint toward the rosebush portal, but something snatches Rosalina’s ankle, pulling her over the edge of a cliff. Her scarf catches on a thorn, leaving her dangling as the goblins stop to watch and mock her. She screams for Lucas, who has nearly reached the portal. He turns and sees her dangling just as the scarf rips, and she falls into the briars below.

A firm presence wraps around her waist, slowing her descent and guiding her safely to the ground. The thorns suddenly animate, rising up and impaling the pursuing goblins. As Rosalina loses consciousness, she has a hazy vision of a man with purple eyes and black hair lifting her into his arms and telling her she is home.

Rosalina awakens alone in the Briar, unsure if her rescue was real. She realizes she was unconscious all night and most of the following day. Following a path through the massive briars, she discovers Castletree, a castle integrated into a giant, sickly-looking tree covered in purple thorns. Believing her father may be inside, she crosses a stone bridge and enters through a huge mahogany door.

The interior is dark, dusty, and invaded by thorns. She notices an ornate rose-framed mirror by the entrance, but resists touching it. A strange, powerful yearning pulls her up a massive staircase into a cloistered tower. She finds herself in a dungeon with barred cells. In one cell, she discovers a young man who is not her father.

The shirtless, fae prisoner has golden eyes and pointed ears, and he’s chained to the wall with a massive collar. He urgently tells Rosalina she must leave immediately because it is not safe, especially after sunset. When she asks about her father, he confirms a human man named George is in the dungeon but insists she must go. Rosalina promises to return and free him after finding her father.

She runs through the dungeon and finds her father in another cell, kneeling and exhausted, but still wearing his moonstone rose locket. He begs her to leave, calling their captors monsters. A shadow falls over them, and ice creeps along the floor and up the cell bars. A deep, gravelly voice from the shadows identifies itself as the master of the castle. The master declares her father is a thief who must remain his prisoner for eternity for stealing a rose.

Realizing her father stole the rose for her, Rosalina offers to serve the sentence in his place. The master steps into the light, revealing himself to be Keldarion back in his fae form—tall and white-haired with glowing blue eyes. He accepts her offer, making her his prisoner and himself her master. Keldarion rips the lock off her father’s cell with his bare hands, throws George out, and puts Rosalina into another cell, locking it. He drags her screaming father away, promising to return him to the human realm unharmed and leaving Rosalina alone as the light fades.

Rosalina spends a fitful night in the cell, hearing a tortured, wolf-like howl from somewhere in the castle. The next day, she looks out her narrow cell window and sees the briars spread for miles, with a distant patch of red that might be roses, marking her route home. She attempts to pick the lock of her cell but fails. Wishing the window were wider so she could climb out, she watches in shock as the stone border glows and the window magically widens, becoming large enough for her to fit through.

Seizing her chance, Rosalina climbs out onto the brambles covering the castle wall. As she descends, a bramble extends to offer her a foothold. The window shrinks back to its original size behind her. She carefully climbs down the five-story wall of thorns. Near the bottom, a bramble breaks, and she falls the remaining distance, landing hard but alive on the stone bridge. Seeing no one around, she sprints across the bridge toward the Briar and freedom. A figure steps out from behind a statue and slams into her.

A tall knight in ornate gunmetal-gray armor confronts Rosalina. He grabs her by the throat, lifts her off the ground, and slams her against the bridge’s barricade, demanding to know if she is a spy for the Prince of Thorns. She kicks him in the gut, and though it feels like kicking metal, he drops her. Enraged, she calls him an overgrown tin can. When she tries to run, he grabs her wrists. She pleads with him, explaining she is a human trying to get home. He asks for her name, and she tells him it is Rosalina, causing his grip to loosen.

The servant girl, Astrid, runs onto the bridge, calling the knight her prince. She explains that Rosalina is Keldarion’s prisoner. Rosalina tries to run again, but the armored prince grabs her scarf and yanks her back. Annoyed with Keldarion, the prince pushes her back toward the castle, but once inside, he takes her up a grand staircase instead of back to the dungeon. Astrid identifies him as Prince Ezryn. He instructs Astrid to make up a room for Rosalina and find her something to eat, stating they are not beasts who throw girls in dungeons.

Ezryn goes to the frost-covered Winter wing, which is covered in ice and crystallized thorns, to confront Keldarion about keeping a human prisoner. Keldarion defensively explains that the girl’s father was a trespassing thief, and she willingly traded places with him. Ezryn is suspicious, as Keldarion has never shown interest in humans or keeping prisoners before.

Ezryn recalls Rosalina’s fiery defiance when she called him a tin can. He tries to ask Keldarion if he thinks the human woman is his soulmate, but Keldarion furiously slams Ezryn against a wall, warning him not to say that word. After a tense standoff, Keldarion releases him and tells him to leave. Ezryn informs Keldarion that he has moved the girl to a proper room and put Astrid in charge of her care.

Rosalina finds herself in a beautiful but dusty room in the Spring wing, covered in cherry blossoms and invaded by thorns. Astrid explains that Castletree is sick and spreading its sickness to the four fae realms in the Enchanted Vale. She warns that the briars are dangerous and controlled by the wicked Prince of Thorns from a realm called the Below.

Marigold, a fae servant, arrives with a cart of lavish food. She assures Rosalina that Keldarion is trustworthy and will have kept his promise to send her father home. Astrid and Marigold discuss the Prince of Thorns, whose real name they’ve been banned from speaking aloud. They explain that the castle has four wings for the four realms, each with a residing high prince and his staff. The staff are permanent residents, unable to return to their home realms.

Marigold makes a lewd comment about Prince Ezryn choking Rosalina, causing Rosalina to flush. Marigold gives her clean clothes and says she will have the staff prepare the room while Astrid takes Rosalina to wash in the hot springs in the Summer wing. She mentions they have not had a guest in 25 years, and the last one ended badly. Intrigued and wanting to learn the castle’s layout for a future escape, Rosalina agrees to go.