Quark's bar is receiving very little business and indeed the only customer in the bar is a Klingon named Kozak. Kozak has run out of money and wants to start a line of credit at the bar. Quark refuses and the Klingon gets so angry he pulls his knife on Quark. As Quark backs away from the Klingon, Kozak stumbles and falls on his own knife killing himself. Quark sees this as a business opportunity and tells everyone that he killed Kozak in self-defense. Quark gets a great deal of notoriety from this - particularly from D'Ghor, a Klingon who claims to be Kozak's brother. D'Ghor asks how Kozak died; Quark attempts to explain that it was an accident, but D'Ghor clearly wants to hear otherwise. So Quark lies to D'Ghor, claiming Kozak died in battle.
After Kozak's widow, Grilka, arrives, she has Quark knocked out and taken back to Qo'noS, the Klingon homeworld. Since women are normally forbidden from leading a Klingon house, Quark is forced to marry Grilka, allowing her to protect her property long enough for Gowron to let her inherit it due to extenuating circumstances (if Quark really had killed Kozak in honorable combat, Grilka would have lost all claims to her House). Quark has to confront Grilka's enemies, leading the temporary "House of Quark". Instead of fighting D'Ghor (who is not Kozak's brother after all), Quark tries to prove that D'Ghor has taken money from Grilka's house for years. However, trying to prove it in the High Council only leads to D'Ghor claiming Quark's accusations as dishonoring him, and leading Gowron to call for a duel of honor. When the time comes for battle, Quark tosses aside his weapon and mocks D'Ghor's efforts, noting that if he does win and claim all of Grilka's property, it will be over the body of an unarmed Ferengi. When D'Ghor happily agrees and tries to kill Quark, he reveals his greed and dishonor to the Council and Gowron banishes him while commending the Ferengi for his bravery. Realizing the "unusual circumstances" underlying the matter, Gowron agrees to let Grilka become head of her House. Grilka is grateful to Quark for his efforts, and he asks for a divorce, which she happily grants in customary Klingon fashion.