- Star Trek: The Motion Picture
- Star Trek II: The Wrath of Khan
- Star Trek III: The Search for Spock
- Star Trek IV: The Voyage Home
- Star Trek V: The Final Frontier
- Star Trek VI: The Undiscovered Country
- Star Trek Generations
Zek, the Ferengi Grand Nagus, pays a visit to Deep Space Nine and moves in to Quark's quarters, where he undertakes an important project. After displacing Quark from his home, the Nagus reveals that he has been rewriting the Rules of Acquisition. Overcome with excitement, Quark and his brother Rom rush to read the volume, thrilled to have a head start on what they think will be the path to unimaginable profit. But they are shocked to read the first rule: "If they want their money back ... give it to them."
Quark and Rom read through the New Rules of Acquisition, which have been revised to reflect qualities of kindness instead of profit and greed. Amazingly, Zek is advising his people to change their ways. Quark is mortified, especially after he later discovers that Zek has established a Ferengi Benevolent Association — and named Rom the senior administrator of the project.
Zek believes Rom can be molded into a new kind of Ferengi who operates "beyond greed." But Quark will have nothing of it — he is convinced something is wrong with the Nagus. He is unsure what to do next, until Zek tells him about the gift he plans to present to the Bajoran people. Quark and Rom later sneak into the Nagus's shuttle to see the gift for themselves, and are astonished to find one of the missing orbs of the Bajoran prophets.
Against Quark's warning, Rom opens the box containing the orb. Quark is exposed to the sacred object, which shows him a vision in which the Grand Nagus reveals the New Rules of Acquisition were a gift. After recovering from the experience, Quark realizes the Rules are not a gift to the Ferengi people, but a gift to Zek from the aliens within the wormhole. Checking Zek's logs, Quark learns that he did visit the wormhole for a brief period, during which he could have communicated with the aliens. Quark surmises that he was hoping to use their ability to see through time to make profit, but something must have gone wrong. He decides the only way to help Zek is to take him back to the wormhole.
Inside the wormhole, Quark encounters the aliens, who explain that they were so bothered by their encounter with the materialistic Zek that they restored him to an earlier, less adversarial state of existence. They threaten to do the same to Quark, but he instead offers a bargain — if they return Zek to his original state, they will never be bothered by another Ferengi. The aliens agree, Zek is back to normal, and the Ferengi way of life is saved.