In 1914, Leonid was taken prisoner and held at Dusterstadt on the banks of the Danube River in Germany. Although Leonid and Yuri, a fellow captive, came up with several escape plans, for two years the Russians weaved a rope out of string from the prisoners' mail.
When Indiana Jones arrived in 1916, Leonid and Yuri informed him of their escape attempt in the belief that as all Americans were cowboys, Jones was the ideal candidate to wield their rope and lasso a spike on the building opposite which would provide a bridge over the steep drop so they could make their break for freedom.
Jones agreed to help but during their escape attempt the rope snapped as the Russian pair were making their way across it. Leonid and Yuri fell to their deaths in the waters of the Danube.
The next day, Dusterstadt commander Otto Richter presented Leonid and Yuri's bodies to the inmates as proof that the prison was inescapable.