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".
In the 1950s, an army reconnaissance group finds an enemy spy organization lurking in a coastal town in southeast China intending to collect military intelligence.
Unfortunate events beset a poor Chinese girl as she escapes from invading Japanese forces, narrowly avoids being raped, and seeks solace in a neighboring village.