The kidnapping of Patty Hearst in 1974 by the Symbionese Liberation Front - a rag-tag, cult-like group of political extremists and criminals - stole headlines across the globe. But then Patty appeared to join her captors, adopting a revolutionary name, Tania, and taking part in a crime spree across California. Why she did what she did, and what happened next, has fascinated the world ever since.