Plot: Exploring the historic walled city of Derry Londonderry, the first UK City of Culture, poet and author Nick Laird looks back at a year of dramatic spectacle and asks how art has healed decades of sectarian violence. Meeting Frank Cottrell-Boyce, author of the London 2012 opening ceremony, he is dazzled by the Return of Colmcille, Boyce's spectacular imagining of the return of the city's patron saint