Filipp Dorofeyev, the editor-in-chief of the publication “Formulist,” dies under mysterious circumstances. Before his death, he leaves a message for his colleagues and the police—a reference to Fermat’s theorem, well known among mathematicians. Investigator Kartashova asks Olga Barkovskaya for help, and Olga quickly realizes that members of a secret Fermatist club are involved in the case. To find out how the events unfold, watch “Fermat’s Enigma” online on ivi.