After being jilted by her fiancé on their wedding day, Kalina embarks on a unique business venture aimed at addressing the issue of male infidelity. She offers her services to women who want to test their partners’ loyalty. Her enterprise runs smoothly until she is tasked with seducing Maciej, a coach and expert in relationships. His wife, Beata, suspects him of infidelity and seeks undeniable proof. Aware of the caliber of her “opponent,” Kalina intensifies her efforts, but this time her strategy falters. Maciej proves to be unlike the other men who were easily exposed for cheating.