A romantic intrigue unfolds against the backdrop of nighttime Moscow. The protagonist, a young journalist named Mark, in search of inspiration and new stories for his articles, accidentally encounters a mysterious woman named Kismet. She appears in his life like a mirage, leaving an indelible mark on his thoughts. Enchanted by her mystery and extraordinary aura, Mark decides to learn more about the stranger. He delves into an investigation that leads him into a world he never knew existed. Kismet, possessing unique knowledge and access to archives, opens doors for him to the secrets of Moscow's architecture and underground communications that have existed for over a century. With each step of their joint investigation, the protagonists get closer to unraveling the mystery of ancient tunnels that may still be used for unknown purposes. Mutual trust and interest grow into something more as they face dangers together and uncover secrets that could change their lives forever.