The events of the story take place in Romania in 1944 during the Great Patriotic War. A German offensive breaks through the defensive line. The Soviet troops fall back, and the crew of anti-tank weapons is cut off from their units for three days. Fate brings together, in the same front-line trench, people from different backgrounds; they must hold back the advance of enemy forces. German tanks go into battle. And opposing them will be a 45-mm gun. In a situation of constant, mortal danger, human characters are revealed…