Lucy, portrayed by Emily Browning, is a university student juggling multiple jobs to make ends meet. She works as a volunteer test subject in a medical research lab, serves coffee at a local café, and makes photocopies in an office. As if that isn't enough, she also navigates the nightlife by attending a swanky bar where she offers her services as a companion for the evening. Despite her efforts, she faces conflict with her landlord and finds solace in the company of an indifferent man named Birdmann (Ewen Leslie), who is drawn to her. Although she doesn't reciprocate his feelings, being with him provides her a fleeting sense of happiness.
Upon responding to an intriguing ad, Lucy meets Clara (Rachael Blake), who introduces her to a unique job opportunity: working as a freelance server in lingerie. Clara assures Lucy that she will never be in a compromising situation during these assignments. Under the pseudonym Sarah, Lucy undergoes beauty treatments in preparation for her debut event. Arriving at a formal dinner party, she is one of the few dressed in white lingerie amidst a sea of older women in darker attire. After serving drinks and pocketing some cash, Lucy’s encounters with Clara evolve into something more troubling.
Lucy soon finds herself at a picturesque country mansion where Clara informs her that after a cup of tea, she will drift into a deep slumber. In a state of sedation, Lucy is seen lying in a vast bed as Clara introduces her to an older man, reminding him of the strict no-penetration policy. The man disregards this rule, fondling Lucy while she remains unconscious.
Facing eviction from her current living situation, Lucy's financial struggles lead her to rent a pricier apartment. After a series of troubling sleeping sessions at Clara's whereabouts, she is summoned to Birdmann, who has succumbed to an overdose. In a moment of despair, she joins him in bed but fails to help as he breathes his last. At the funeral, her detached demeanor prompts a man to refuse her unexpected marriage proposal, highlighting her emotional turmoil.
With her office job lost, Lucy acquires a discreet camera and spirals further into drug use with a coworker, culminating in a hazy encounter that leaves her waking up naked beside him. Late for her next assignment, she’s determined to uncover the secrets behind Clara's shadowy operations. When she pleads to witness the events during her unconscious state, Clara quickly dismisses the request, citing possible repercussions.
However, Lucy ingeniously manages to hide a camera in her mouth during one of the sessions. Awakening at a crucial moment, she sets her device just before falling back asleep. Once again, the familiar man appears, ingesting tea laced with a higher dosage of sedative. The next morning, Clara discovers the man's lifeless body next to Lucy, who awakens screaming in horror.
The film concludes with a haunting image captured from Lucy's hidden camera, revealing the heavy silence of the room—a juxtaposition of innocence and mortality, leaving viewers to grapple with the chilling events that transpired.
