DS9 Season 2 Episode 7 Rules of Acquisition

Plot

Grand Nagus Zek, the leader of the Ferengi, plans to establish a business presence in the Gamma Quadrant. Zek appoints Quark as his representative to negotiate with a species called the Dosi; Quark asks Pel, one of his employees, to assist him. Pel proves to be a valuable assistant; however, unbeknownst to Quark, Pel is a female. Ferengi females are not allowed to wear clothing, earn money, or travel, so she is forced to keep her identity a secret. Meanwhile, Pel begins to fall in love with Quark. She confesses her secret to Deep Space Nine's science officer Jadzia Dax.
Quark and Pel ask to purchase 10,000 vats of tulaberry wine from the Dosi. They are close to making a deal when Zek informs Quark that he wants 100,000 vats. The Dosi abandon the deal. Quark and Pel follow them to their homeworld, where they learn that 100,000 vats is more tulaberry wine than exists on the planet. A Dosi offers to put them in contact with another race, the Karemma, a member of what she calls "The Dominion". Quark and Pel realize Zek's true intentions: He has no interest in tulaberry wine; he wants to learn about the Dominion.
Quark and Pel return to DS9. While they were gone, Quark's brother Rom, jealous of Quark's preference for Pel over him, discovered Pel's true identity. He tells Quark, who realizes his career could be ruined if he were known to have done business with a female. Quark confronts Pel, offering her money to leave and start a new life, in order to save her and himself from punishment. Pel confesses her feelings for Quark and pleads with him to come with her to the Gamma Quadrant, where no one would mind that she is a Ferengi female who makes profit. Quark refuses, though he has feelings for Pel as well.
At a dinner celebrating Quark's negotiating success, Pel reveals her identity to Zek. Zek threatens to put Pel and Quark in prison, but Quark defends Pel by observing that Zek himself unknowingly allowed a female Ferengi to represent him. Realizing that they were all misled, they decide to keep Pel's identity a secret. After sharing a heartfelt goodbye with Quark, Pel leaves to start a new life in the Gamma Quadrant. Some time later, Dax comments that Quark will miss Pel, though he tries to deny it.