A narrow stretch of water is all that separates the People's Republic of China, ruled by the Communist Party, from Taiwan, Asia's most successful democracy.The small island is in dire straits, stuck in the middle of a struggle between two nuclear powers — China and the United States. There are real fears it will soon become the centre of the next major global conflict.While China insists Taiwan must re-unify with the motherland, Taiwan's president says the island must maintain its freedom and democracy.This week's episode of Four Corners goes inside the fight to tell a story that could have ramifications for us all.We meet young people training in urban warfare who are bracing for more cyber-attacks, disinformation and the possibility of an all-out battle.A pro-Beijing campaigner and a former gang leader explains why they want reunification and shares footage of his party members battling pro-independence students.And we tackle the question: what next for Taiwan?