About a young boy who tries to keep an eye on his little sister and save her from trouble. But when the parents return home, the boy's ideal world collapses.

Arina is about to become an adult. Along the way, she will have to take the entrance exams and face the challenges of making the right choice. But all she can think about is the upcoming summer and Vitia. This is the story about growing up and ability to hear your inner voice.

The film takes place during the full-scale Russian invasion of Ukraine. After the Kakhovka dam is blown up, a detachment of Ukrainian soldiers led by a female fighter with the call sign Mara finds themselves in a secret Soviet bunker at the bottom of a reservoir where the USSR conducted human experiments during the Cold War. The consequences of these experiments are still in the bunker in the form of the half-living corpses of Soviet soldiers. Now, in order to survive, Ukrainians need to defeat the Soviet zombies, their own fear, as well as overcome internal disputes and trust each other.