Sarah (Jodie Comer) is smart, but she's never fitted in, not in education and not in work. Her family told her she'd never amount to anything but she unexpectedly finds her calling as a carer at Bright Sky Homes. Sarah has a special talent for connecting with the residents, including one in particular, 47-year-old Tony (Stephen Graham). Tony's Young Onset Alzheimer's has left him living out his days in care as his mind slowly deteriorates. His illness causes periods of confusion and violent outbursts, which the other members of staff can't handle, but with Sarah he begins to build a real bond. Sarah's success at managing Tony and the other patients helps build her confidence and restore her self-belief. Then March 2020 hits and everything Sarah has achieved is thrown into doubt with the arrival of the Coronavirus pandemic. She and her colleagues tirelessly fight tooth and nail, ill-equipped, poorly prepared, and seemingly left helpless by the powers that be. A determined Sarah goes to extraordinary lengths to protect those in her care, whose conditions make their suffering and isolation all the more traumatic. But the staff's unwavering commitment, compassion and heroic efforts can only do so much, and Sarah is pushed into a dark corner and desperately looks for a way out.