Kalina (Magdalena Lamparska), a hopeless romantic, learns about her fiancé's infidelity on her wedding day. Her best friend, photographer and vegan dish caterer Fretka (Anna Dereszowska), is betrayed by her partner around the same time. Angry and hungry for revenge on all men, who according to them will always cheat, they set up a unique business whose aim is to test mens' fidelity.

The business model is simple - any woman concerned about her relationship can hire them to see if they can seduce her man. Everything goes well until Kalina falls for her client's husband, Maciej (Mikołaj Roznerski), a coach and relationship specialist, whose wife Beata (Veronica Rosati) suspects him of treason and is looking for supporting evidence.