Trudy Ederle (Daisy Ridley), an accomplished swimmer, was born to immigrant parents in New York City in 1905.
Through the steadfast support of her older sister and supportive trainers, she overcame adversity and the animosity of a patriarchal society to rise through the ranks of the Olympic swimming team, culminating in her attempt to complete a staggering achievement: a 21-mile endurance swim from France to England.