Stalnoe serdtse/Heart of steel/Стальное сердце A long time ago, Nightingale the Robber managed to defeat Ilya Muromets by cunning. He rewrote history, appropriating to himself all the exploits and glory of the hero. Thanks to the elixir of immortality, the Nightingale has survived to this day. And now he wants to revive the dark god Veles, to whom he then sold his soul. Today only the family of our heroes knows this secret. The father of the heroes, Professor Kiselyov, manages to find Muromets in the north, in the ice of an underwater cave, where the last battle between the hero and the robber took place. Thanks to Kiselyov's development - the heart of steel - Muromets returns to our world. However, this feat costs the professor his life. Now his sons, Maksim and Egor, will have to not only stop the Nightingale, but also restore the honorable name of Ilya Muromets - in fights between giant robot warriors at the RoboArena.