 The film was entered into the 1957 Cannes Film Festival.On 19 April 1949, the Royal Navy sloop HMS "Amethyst" sails up the Yangtze River on her way to Nanking, the Chinese capital, to deliver supplies to the British Embassy.Suddenly, without warning, People's Liberation Army (PLA) shore batteries open fire and after a heavy engagement, "Amethyst" lies grounded in the mud and badly damaged.