Huw always pops in to see his nan on the way home from school – she bakes him cakes and never fusses about his homework. And so it’ s a great shock when, one day, Nan forgets his name, and calls him Hywel – the long-unmentionable name of her late brother. As Nan slowly slips into the grip of dementia, Huw and his friends go on a quest to learn more about Hywel and what happened to him.