In 1937, 800 Chinese soldiers fight under siege from a warehouse in the middle of the Shanghai battlefield, completely surrounded by the Japanese army.

The Eight Hundred recounts a key moment in the Battle of Shanghai in 1937 during the Second Sino-Japanese War when 452 Chinese soldiers, led by Lieutenant Colonel Xie Jinyuan (Du Chun), are ordered to defend the fortress-like Sihang Warehouse against the much larger Japanese army. Slowly, the defenders' numbers are whittled down while repelling one enemy attack after another. Meanwhile, the siege is being watched by the initially dispassionate citizens of Shanghai's opulent International Settlement on the other side of Suzhou Creek. As the Chinese soldiers' situation becomes more desperate, it awakens a dormant patriotism that inspires the citizens to help them.

1937: The Second Sino-Japanese War is raging and the Japanese Army has the upper hand. In Shanghai, the Chinese Army is falling back but the 524th Regiment holds on at Sihang Warehouse. The 452 defenders (exaggerated to 800 for the public) hold on against overwhelming odds in what will become an epic last stand.—grantss