During a stormy night in 1816, a group of iconic writers gather for a night of revelry and intellectual stimulation at the Villa Diodati, the mansion of poet Lord Byron. Among the guests are the poet Percy Bysshe Shelley, his future wife Mary, her stepsister Claire, and Byron's physician Dr. John Polidori. Seeking to entertain each other, they participate in various dark experiments and storytelling sessions, aiming to spark their creativity. Their activities soon shift from mere amusement to a deeper exploration of their subconscious fears and hidden desires, creating an increasingly unsettling atmosphere.

As the night progresses, the psychological tension intensifies, blurring the lines between reality and nightmare. Each character becomes haunted by grotesque visions and their own inner demons, leading to hysteria and paranoia within the group. Amidst this backdrop of chaos and terror, creativity is ignited, leading to the birth of some of literature's most legendary works. The group's encounters with their fears and the supernatural elements around them drive them to explore the boundaries of human experience and imagination, forever altering their lives and contributions to literature.