This lively family entertainment film is about a group of children battling with a pair of musical con-men who stage a fake singing contest. The unfortunate duo hadn't anticipated the talents of Maestro Soong with his remarkable children's choir. What ensues is a string of hilarious, heartwarming, and ultimately inspiring events.

In 1937, after the Marco Polo Bridge Incident, the Second Sino-Japanese War breaks out. San Mao, a wandering orphan, joins the army to participate in the Battle of Shanghai.