A harmless retired woman, a former doctor, is killed in the entrance. And two days later, her friend, who once worked with her as a nurse, dies... The children of the murdered, journalist Dima Poluyanov and librarian Nadya Mitrofanova, are trying to understand whether these two deaths are related. And they find out that quite recently the former chief doctor of the clinic where both women once worked also died... All the threads of this strange case lead to St. Petersburg. Dmitry and Nadya go there, especially since ruthless killers are hot on their heels in their hometown. And so far the fugitives have only miraculously managed to escape from their clutches. However, luck is a fickle thing. Therefore, you need to be the first to find the people who are behind it all. Otherwise, every day for Dmitry and Nadezhda could be the last...