An action detective about the investigation of an experienced investigator Maksym Kholod and a linguistic forensic scientist Oleksandra Kosovych, who solve the most complex criminal cases with only voice messages, personal diaries, farewell letters, or notes of victims. For the impulsive, rude, and rather severe Kholod, work is a "battlefield" where he can get sharp emotions and a sense of risk. Principled and unyielding Kosovych, on the contrary, is guided by a cold mind, her main tool - knowledge of the language, texts, and words. Despite the different methods of work and motives, only together can they find out the reasons for the mysterious suicide of Kholod's daughter.