Presented by Rene Cutforth
On 23 March 1929 the US Coastguard sank the British schooner "I'm Alone" in the Gulf of Mexico. They suspected her of rum-running for a gangster like Capone.
The US authorities needed proof that the "I'm Alone" was working for an American gang. To find it, they called in Mrs Friedman, America's top code-breaker.
Taking part in the programme is Mrs Friedman herself, and the coastguard who sank the "I'm Alone".