Set in the vibrant backdrop of 1880, this film explores the groundbreaking invention of the vibrator through the eyes of Dr. Mortimer Granville, a young physician struggling to find his footing amidst the ongoing debates surrounding modern medicine. Initially, he takes a position assisting Dr. Dalrymple, a physician renowned for his unconventional practice that caters to women diagnosed with "hysteria." During this era, "hysteria" was often treated through a rather peculiar method involving the massage of the genital area, performed discreetly behind a curtain to provoke what they referred to as “paroxysmal convulsions.” However, unbeknownst to them, these methods were inducing orgasms instead.
As Dr. Granville delves deeper into this unique medical practice, he encounters Dr. Dalrymple’s two daughters: Emily and her spirited older sister Charlotte, who is portrayed as a pioneering feminist dedicated to running a settlement house in a struggling area of East London. Granville's talent for the unconventional treatment quickly earns him a devoted clientele, and Dr. Dalrymple envisions a future where Granville might take over his practice, as well as marry Emily, which adds a layer of personal complication to their professional relationship.
One evening, Charlotte arrives with her friend Fannie, who has suffered an ankle injury. Granville’s willingness to assist prompts Dr. Dalrymple to forbid him from helping her again, hoping to sway Charlotte from her work in the less fortunate neighborhoods. The growing demands of his practice take a toll on Granville’s physical capability, leading to a debilitating cramp that ultimately results in his dismissal. Fortunately, his inventive friend, Lord Edmund St. John-Smythe, shows him an innovative electrical feather duster; its vibrations spark an idea in Granville's mind about adapting it into an electric massager.
After successfully testing this new device on the Dalrymple's maid, Molly, Granville convinces Dr. Dalrymple to employ it with his patients, resulting in an overwhelming success for the practice. This unfolds as Mortimer and Emily get engaged, while Charlotte tirelessly works to sustain her settlement house.
The story takes a dramatic turn during the engagement celebration as Charlotte is arrested while defending Fannie from a police officer. Both Emily and Dr. Dalrymple pressure Granville to testify in a way that would suggest Charlotte is merely "hysterical," in hopes of sparing her from more severe punishment. When the trial unfolds, the prosecutor calls for her commitment to a sanatorium and a hysterectomy. In a powerful moment, Mortimer asserts that the symptoms of hysteria are too widespread to qualify as a mental disorder, emphasizing Charlotte’s inherently benevolent nature. The judge agrees with his reasoning, resulting in Charlotte receiving a 30-day sentence instead of harsher repercussions.
After this tumultuous incident, Emily comes to realize that her engagement to Granville was primarily an attempt to appease her father rather than stemming from true love. As the vibrator begins to be recognized as a legitimate medical device—significantly cutting down treatment times and enhancing patient satisfaction—Granville finds himself financially independent, but acknowledges that his heart belongs to Charlotte.
In a grand gesture, he vows to utilize a portion of his new wealth to create a clinic at her settlement house, leading him to propose marriage to Charlotte. Their shared passion and vision ultimately bring them together, culminating in her acceptance of his heartfelt offer.
