Hidden from public sight, some of Japan's most terrifying atrocities during World War II were carried out in secret laboratories across Asia. The notorious Unit 731 and related biological warfare units conducted germ attacks, chemical experiments, and live dissections on civilians – crimes so brutal that even postwar tribunals were shocked.

Researchers and former Unit 731 members reveal how these military units had expanded in China since Japan launched invasion and later spread into Southeast Asia. Uncovered records from Myanmar, Malaysia and Indonesia further expose a chilling truth: these inhumane experiments were far more widespread than once known.