In A Mayhem of Cars Danny discovers he is rather good at imitating the sound of a horse while Cate consults her book on collective nouns for inspiration as the duo delve into the world of transport and look at how we are going to be getting around in the future. They find out about electric rickshaws in Delhi and all about India's first solar ferry. How parents and school kids in Barcelona are taking over the streets and they discover the first city in the world where all the public transport is already electric.