The film is based on the novel "The "Mary" Diamond" by Yuri Scop. Maria and Ivan work on a diamond factory. The day of their wedding will come soon, but Ivan is tormented by the past: during his stay in prison, a gang leader gave him a bag with diamonds for safekeeping. To return the "stones" to the factory means to declare himself as a punter, to throw away – to be always sorry, to keep them for Mary – to destroy love. Soon his "friend" put himself on the map and demanded to repay. And Ivan decided to settle accounts with the bandit...