The series begins in the summer of 2019 and follows 43 year-old Chris, as he awaits news of his daughter's blood test results for the same gene and faces a big test himself: his driving assessment.Gilly, 74, and his wife Christine are trying to make the best of their retirement, spending time with their friends at their holiday home in Spain and with their grandchildren back in Bradford. But as Gilly's dementia progresses, Christine finds it harder to cope with her care needs.For Clover, 89, things take a turn for the worse when she puts an electric kettle on the gas hob, setting fire to the kettle. As a result, her daughter Marcia is faced with some difficult decisions about the future of her mum's care.Recently diagnosed Marion, 61, has been adapting to her symptoms by redesigning her house to make it easier to find her way around. She also takes part in a research project that reveals that she can no longer read a series of numbers in a sequence.