This is an automatically translated description

Did you know that you can get to the Other Kyiv through the old abandoned branches of the Kyiv metro? It was built at the same time as the regular one, but it is home to many strange creatures and interesting people. The Other Kyiv is in danger - dark forces want to destroy it. Disaster is also looming over ordinary Kyiv, and the city may not be able to withstand the enemy.

Fifth-grader Marko accidentally meets Lyubava, a girl from the Other Kyiv, although he has no idea what a dangerous adventure it will be for him. But why did this happen to him? Perhaps the reason lies in some old family secret that Mark's mother does not want to tell him about? But the boy has no time to think about it - he has to save Kyiv from the attack of the insidious Demon. Together with Mark and Lyubava, knights from the past, Ukrainian heroes, and even otherworldly forces stand up to defend the city. However, the Demon does not give up easily and can cause a lot of trouble. Will Kyiv survive?