In 1958 in Kenya, Robin Cavendish [Andrew Garfield] falls ill from polio at age 28, not long after meeting and marrying his wife Diana Cavendish [Claire Foy]. He is left paralyzed from the neck down and unable to breathe without a respirator, with doctors offering only about three months to live.
Robin is repatriated to Britain. At first, he sinks into depression, withdrawing from his wife and their newborn son, Jonathan [Dean-Charles Chapman], even wanting to be taken off life support. Diana fights to keep his spirits up, visiting him and slowly helping him regain a sense of hope.
Realizing she can provide daily care, Diana suggests bringing Robin and the respirator home. With the strenuous objections of the hospital consultant Dr Entwistle and the support of some doctors and nurses, Robin is brought home and reunites with his son. When Jonathan is playing with his dog, the animal knocks out the ventilator’s plug; Robin, unable to move or speak, cannot signal Diana, and she eventually finds him unresponsive and replugs the machine.
Seeing his son push a pram sparks a new idea for Robin: a mobile chair with a built‑in respirator. He enlists his friend Teddy Hall, Hugh Bonneville, to help build one. With the chair, and the help of Diana and her two brothers, Robin is able to venture beyond the home for the first time, and a specially built van allows the family to travel further—even flying the van on a cargo plane to Spain.
Teddy continues to refine the design, and Robin teams up with Dr Clement Aitken to produce more of the chairs. He returns to his original hospital with many of Teddy’s chairs, and the other patients in the ward leave with him, seeking a freer, more humane life.
After witnessing a German hospital that confines severely disabled patients like prisoners, Robin appears at a conference and urges doctors to treat patients with greater humanity, earning a standing ovation.
Years later, Robin faces serious bleeding due to his extended use of the respirator and decides to stop prolonging his life. He discussions this with Dr Aitken, who cautions that Diana and Jonathan cannot be involved. Robin hosts a farewell party for friends, then asks his family to leave and return to the house at precise times.
Jonathan, now in his thirties, and Diana watch as Aitken drives away, and they return to the house. In his fading moments, Robin expresses love for both of them and dies, having forever changed the lives of many others who suffer as he once did.
