The Romanian Ministry of State Security has learned that foreign intelligence is hunting for plans for blue mines, where strategic raw materials are mined. This task is carried out by a gang led by a spy named Sea Cat.

Adam, a young and poor fisherman, falls in love with Uliana, but the girl's parents want her to marry Simion. To get rid of him, Simion blames Adam of the drowning of his fellow fishermen he was with out in a storm.

Famous Romania communist propaganda movie, one of the templates to what followed. It is about the volunteers that built the Bumbești-Livezeni railroad.