It's the half-term holiday and George Kranky is looking forward to a break from school when a letter from Grandma arrives announcing that she is coming to stay – that very day! Soon she is making George's life miserable with spiteful comments and demands for doses of medicine, so George decides to mix a new type of medicine for her. Shaving foam, shampoo, lipstick and chilli powder all go into the mixture, which makes Grandma grow and grow into a giant until she crashes through the farmhouse roof. Soon Dad comes up with a plan to use the medicine to make giant farm animals – and a fortune for the Kranky family. First George needs to remember the ingredients for his marvellous medicine, with a little help from the audience.