Sarah was sixteen years old during the events of the film 1985, Born in the Year 1969. Sarah was the only child of Robert and Linda Williams, and proved to be highly imaginative, her love of fantasy and theatrics inspired by her mother's acting career. Linda walked out on her family to be with her lover, an actor called Jeremy. After divorcing Linda, Robert married again to a woman called Irene. They had a son called Toby, and Sarah was bitterly resentful of both Toby and Irene. Sarah's dislike of her father's new family was intensified by the strong bond she maintained with her mother, whose exciting lifestyle made her scornful of her dull suburban existence. When Toby was around a year old Sarah wished him away to the goblins in a fit of jealousy, and the baby was taken to the castle of Jareth, the Goblin King. Sarah was challenged by Jareth to travel through his Labyrinth and win back her brother from his castle, and was given thirteen hours to complete the quest. With the help of the friends she met on her journey, Sarah succeeded, defeating Jareth and returning home with Toby. Her journey through the Labyrinth taught Sarah to be more responsible, and made her appreciate the love she felt deep down for her brother (Labyrinth.) Sarah continued to draw comfort from her love of fantasy, sharing her passion for make-believe by telling Toby fairy-tales and stories from her imagination. She maintained contact with her friends from the Labyrinth, their companionship serving as a source of reassurance when she was in need. Sarah also worked hard to fulfill her ambition of becoming an actress, participating in an acting club at high school. When she was seventeen or eighteen Sarah's application to the Juilliard School, a prestigious performing arts college, was rejected. This rejection shattered Sarah's dreams of becoming an actress, and she fell into a state of despair. Jareth - who had fallen in love with Sarah - asked the sorceress Mizumi to form an ablation out of Sarah's dreams, intending to keep it with him as a companion as he could not have Sarah herself. Sarah wanted her dreams to be taken as they caused her too much pain following her rejection from Juilliard, and the ablation was formed with her tacit consent. The creation of the ablation left Sarah dreamless, and with her ambitions to become an actress gone Sarah appeared to mature overnight. She started taking her school work seriously, and went out on dates for the first time. Sarah cleared out all her toys, giving some to Toby and selling the rest. Her memories of the Labyrinth had been taken along with her dreams, so all contact with her friends from her adventure there ceased. After graduating from high-school, Sarah went to college and studied to become a teacher. She became a teacher of English Literature at a Junior School, where she was notoriously strict.

Jareth, first seen in owl form, confronts Sarah, who must rescue her brother Toby within thirteen hours. He offers her a crystal but vanishes, leading Sarah into the Labyrinth. In his castle, Jareth interacts with goblins and attempts to manipulate Sarah through various tricks, including offering a peach that makes her forget her mission. He appears in a dream-world, dancing with her, yet when Sarah remembers her goal, he is left watching as she escapes. Ultimately, Jareth confronts Sarah in his castle, where she resists his temptations and defeats him by declaring he has no power over her. The film reveals Jareth as a complex character—proud, clever, and charming, exhibiting feelings toward Sarah, while also embodying traits of a self-centered ruler. Director Jim Henson noted Bowie's portrayal as devilish rather than purely evil, blending humor with his rock star persona. Despite Jareth showing no signs of anger at Sarah's rejection in the film, the non-canon Return to Labyrinth series depicts Jareth as a sore loser in the wake of Sarah's victory, unable to accept his defeat at the hands of a young girl. He is characterized as very domineering when given the opportunity, with his main goal following Sarah's defeat of him being able to make her forget her own dreams and bend to his will. However, due to the fact that he lets her leave to follow her dreams at the end of the series, this proves Jareth truly does love Sarah. He cares for Casimir as if they truly were his child. He brought Casimir to the Labyrinth when Casimir was just 12 in human years (though actually much younger in fae years). He would never admit to caring for Casimir but he knows them very well, sometimes telling them stories (and tolerating Casimir when they sometimes fall asleep during said stories). He's very aware of Casimir's actual age rather than just their age in human years. He can almost always tell what mood Casimir's in, as the Labyrinth/palace often reacts to their emotions and moods. Jareth has distinctive long blond hair styled in a mullet and wears various costumes throughout the film, including a velvet tailcoat and eye-catching accessories. He possesses magical abilities such as shapeshifting into an owl, manipulating crystal balls, and defying gravity, showcasing his powers in the Labyrinth.