Friends serve in the same military unit - commanders of tank battalions, majors Oleg Sedov, Vladimir Likhachev, Ivan Zverko. During a training exercise, Sedov makes a risky decision to break through the swamp. His battalion manages to be the first to occupy the height, but Likhachev’s battalion is only ten minutes behind the first battalion, but at the same time Likhachev, as always, remains cautious and does not agree to the risky proposal to go through the swamp. Sedov pays severely for his recklessness. One of his battalion's tanks overturns and falls into the swamp...