Unit 731

The film is a graphic depiction of the war atrocities committed by the Japanese at Unit 731, the secret biological weapons experimentation unit of the Imperial Japanese Army during World War II. The film details the various cruel medical experiments Unit 731 inflicted upon the Chinese and Soviet prisoners at the tail-end of the war.

In 1935, Japan's Unit 731 conducts inhumane experiments. A doctor tries to free prisoners, including his fiancée, from the camp while witnessing atrocities.

During the shut down and destruction of the Japanese test camp Squadron 731 in Manchuria, a soldier becomes infected with a virus developed during the camp's testing and risks spreading it into Japan on the train ride home.

Black Sun: The Nanking Massacre depicts the brutal events behind the Nanking Massacre committed by the Imperial Japanese army against the Chinese people during the Second Sino-Japanese War.