In summer 1975 at the Constanța Shipyard, director Mihai Coman pushes to cast a massive ship propeller in-house, facing technical failures, internal resistance, and political hesitation. As the casting repeatedly breaks and deadlines loom, he must overcome engineering hurdles and personal sacrifices to see the vessel launched with the home-forged propeller.

罗马尼亚自己制造的第二艘55000吨矿砂船在一次试航中失败了，造船厂厂长科曼决心发扬自力更生精神，依靠广大的工人和技术人员，重新进行铸造。他的试验并没有得到上级领导和工厂党委内部的支持。但科曼厂长坚韧不拔，以革命乐观主义精神与困难做斗争，排除一切障碍，最后终于铸造出了罗马尼亚自己的大型螺旋桨，安装在55000吨矿砂船上。