Marina Kapov is a cleaner at a Zagreb police station and a single mother of three. Although she hides her exceptionally high IQ of 160, her talent becomes impossible to ignore after she accidentally solves a complex case that seasoned detectives failed to crack. Recognizing her abilities, the police hire her as a consultant, pairing her with inspector Tomislav Ramljak, a strict, rule‑bound investigator. Their contrasting personalities gradually turn into a strength as they work together to solve challenging crimes.