Time Team investigate Caerau Hillfort, a huge hill near Cardiff that may be immensely significant; is it the long-lost Iron Age capital of South Wales? Geophysics shows multiple circular marks, indicating several roundhouses. However Francis is initially having trouble locating these structures in the ground. But there are finds a-plenty including a rare early Iron Age cup. They are joined by Iron Age specialist Niall Sharples, who explains that a hill fort's function is primarily domestic and social, rather than military. Kids from Ely are drafted in to help with the dig, and historian Ray Howell shows two of the kids some iron age artefacts in the National Museum Wales. Meanwhile metalworker David Chapman makes a bronze handle for a drinking cup.