Following three children and their families as they undergo both cutting-edge and traditional treatments at the Royal Marsden in London. Cameras follow three-year-old Charlotte, who is one of the first children in the UK to take a pioneering new targeted drug that has saved her life, while toddler Artemis must undergo a stem cell transplant, first done over 50 years ago, as this is the best option available to her. Elsewhere Lily, who is 14, takes on a cocktail of chemotherapy and newer immunotherapy drugs.