At the beginning of 1223, tens of thousands of Mongol-Tatars, led by the military leaders Genghis Khan Jebe and Subedei, invaded the Polovtsian steppes. Polovtsian Khan Kotyan turned to the Russian princes for help. At the council in Kyiv, it was decided to move together to meet the enemy. Soon the Russian-Polovtsian army moved east... On the morning of May 31, 1223, a battle began on the Kalka River, not far from the coast of the Sea of Azov, which marked the beginning of the century-long confrontation between the Horde and Russia. A new novel by the writer-historian Alexander Filimonov is dedicated to the events that took place at the beginning XIII century. The central place in the book is occupied by a detailed story about the first invasion of Rus' by the Mongol-Tatars and the battle of the united Russian-Polovtsian army with them on the Kalka River in 1223.