In 1942, Japanese ship "Lisbon Maru" carrying British POWs was torpedoed. Dongki fishermen rescued 300 Britons, protected 3 during Japanese search after Lisbon Maru shipwreck near Zhoushan Islands.

The film is based on a true history of World War II: In 1942, a Japanese cargo ship "Risbon Maru" carrying more than 1,800 British prisoners of war was torpedoed by an American submarine in the waters near the Zhoushan Islands. Nearby Dongki fishermen risked their lives to rescue some 300 British servicemen, and protected and rescued three Britons during a massive Japanese search. This history is known as the Lisbon Maru shipwreck.