In the beginning of the Nazi occupation of Belgrade, a group of young immigrants arrive in Belgrade to execute special assignments for the Partisans, the first objective: rescue a fellow Partisan from an occupied hospital.
Tihi reconnects with an old flame Lili to gain access to a German motor garage while the rest of the gang infiltrate an ammo dump to obtain explosives for the sabotage.
As the charismatic Major Krieger tightens the noose, the Partisans begin to suspect a traitor called Beli is among them. A new liaison from HQ is assigned to the Partisan cell and she orders the assassination of the chief of police.
Destroying a German explosive depot proves to be an immense task for the Partisans due to the imminent flooding of a sewage system they must use to reach the depot.
A munitions train headed to the Eastern Front must be blown up so Prle recruits his neighbor, Joca the postman for a way in. Complications arise when Gestapo orders Joca to escort the very same train.
A villa containing the plans of army groups in the area hosts an officer's ball. With the aid of Vlada Rus, the Partisan's inside man, Prle, Tihi and Sirano infiltrate the premises to retrieve the plans.
Krieger begins to suspect Vlada Rus. The Partisans, following Paja's death, plan to destroy the army unit stationed nearby. With dwindling supplies and manpower, fresh faces arrive to help.
A string of arrests and tortures starts a game of cat and mouse between Slavko, the Partisan's inside man in the collaborating police and Misic, the head of the very same division.
A risky operation forces the Partisans to evacuate wounded over the Sava river. The barge in which Tihi, Cibi and their uncle live serves as a meeting point. Krieger is hot on their heels after Tihi's schoolmates reveal his location.
Believing the Partisans are eliminated, Krieger and Misic arrange to meet at a shipyard to assess its security. Prle and Tihi are tasked with sabotaging the same shipyard.
