Diana (Claire Foy) and Robin Cavendish (Andrew Garfield) are two young people who fall in love with each other and it is not long before the two decide to take the big step of the marriage, and then Diana gets pregnant with a little boy They will call him Jonathan. Their seemingly unshakable happiness is ruined when it is discovered that Robin suffers from poliomyelitis and will only have to live for months, and he also has a diagnosis of irreversible paralysis.
At first, he can not even speak, only succeeding in moving his eyes hard. He is put on a device to keep him alive and is informed that the hospital bed will most likely find his end. He is resigned to the news and asks for his suffering to be cut off by disconnecting him from the devices that still keep him alive.
However, Diana is not as resigned as he is and convinces him that he has to fight until the last possible blow and try to spend as much time as possible with their boy. As he begins his struggle, he takes this battle as far away as no one has before him. When Diana is informed that her last days will have to spend in the hospital, they plan a plan to bring life-support equipment to her home, even if the doctor protests. Later, the two take their plan even further.