Somewhere between a family therapist and private investigator, the titular mistress dispeller, Wang Zhenxi, follows husbands suspected of having an affair, gets to know them, gets to know the mistress, and sits everyone down for one of the most uncomfortable conversations of their lives. Elizabeth Lo’s documentary on Wang and one of her couples carefully avoids the exploitative bits of this conversation to focus on the more interesting bits, such as what it takes to maintain a relationship in contemporary urban China and what it takes to mend a broken one.