What do King Salman of Saudi Arabia, Icelandic Prime Minister Sigmundur David Gunnlaugsson, Ukrainian President Petro Poroshenko and the movie star Jackie Chan have in common? Their names all turned up in the Panama Papers, the biggest known leak of documents in history, detailing how a financial services firm in Panama hid billions of dollars from tax authorities for the rich and powerful, using an array of shell companies and proxy owners to confuse the trail and protect the anonymity of wealthy clients. How to translate this deliberately bewildering movement of cash into a compelling story, in print and on screen?