Set in the China civil war period in 1940s. A KMT pilot finishes his study in US and returns China to join KMT air force. But he is disappointed with the behavior of KMT and joins CPC army.
It is a story about the Chinese police who intelligently and bravely fight with the cooperation of the factory's Party Committee and the masses, against the spies, who steal the navy's equipment "Hunting No.99".