Isan Nikah revolves around the upcoming marriage between a Muslim girl from Pattani named Sophia (Kamonporn Sangwatcharasoontorn) and her lover, Bak Kai (Nattawut Sanyabut), who hails from a district in Thailand called Isan. Bak Kai, originally a Buddhist, converts to Islam in order to marry Sophia. However, the marriage is not approved by Sophia’s brother, Bang Lee (Amadkuciasree Doloh), who suffers from emotional issues due to trauma caused by their mother abandoning the family and marrying another man from Isan. Bang Lee does everything he can to sabotage the wedding between his sister and Bak Kai, leading to a series of humorous and chaotic events.