The Enterprise is on a routine science mission, studying protostars in the Volterra Nebula, when Picard receives a puzzling invitation to the observation lounge from Riker. Entering to see a statuette highlighted on the table, Riker brings the lights up to reveal a guest, Professon Galen, Picard's old mentor from his days as a xenoarchaeology student.
The captain is overjoyed at this surprise visit. After they exchange heartfelt greetings, he eagerly resumes the role of pupil as Galen quizzes him on the Kurlan naiskos, a gift from his recent explorations, sitting on the table. Picard gushes over the extraordinarily rare find, in excellent condition despite how distant — both in space and time — its origin is from the Federation.
The conversation turns serious as Galen teases Picard about some new research he has been doing over the past decade, an impending discovery that he claims will shake the galactic community to its core. But he won't say any more unless Picard agrees to help him finish the work in what will be a long and potentially dangerous journey into the frontier. It would mean giving up his command, perhaps his entire career in Starfleet. Picard can't bring himself to do that, no matter how tempting the adventure. The professor is personally affronted at being refused — again — by his favorite student, throwing back several cutting invectives before storming back to his shuttle.
Some days later, the Enterprise receives a distress call from Galen's shuttle, which has been boarded by a hostile Yridian ship. Picard orders it disabled, but somehow even a single low-power phaser beam causes it to explode spectacularly. Galen, mortally wounded by a disruptor, is beamed to sickbay. He only manages to say one thing as he dies.
With both Galen and his attackers dead, the crew have only the shuttle's computers to shed light on what happened. What little data they can retrieve, a series of numbers, is presumably part of Galen's mysterious research and what the Yridians were after, but means nothing to them without further context.
A new clue emerges at Galen's intended destination, Indri VIII, which has been scoured of what little plant life it had by an unknown party. With the presumption that it is related to the research, the computer identifies the data as an assortment of ancient DNA fragments from across the quadrant. Such disparate fragments should have no relation to each other, but Crusher notes that they have similar protein configurations. They connect to form an algorithm that could only have been deliberately engineered.
They must find the missing fragments to discover the purpose of the program. It seems they are out of leads, until Picard remembers Galen's gift from the Kurlan system. The only life-bearing planet there, Loren III, is not among the DNA fragments, possibly stolen by the Yridians.
The Enterprise arrives to find not one, but two interested parties: the Cardassians and the Klingons, neither of whom are interested in sharing what they are convinced will be some cool ancient technology. Picard convinces the captains, Gul Ocett and Captain Nu'Daq, to see reason. If they don't cooperate, no one will find all the pieces. As luck would have it, there is only one piece missing between the three of them, so they have the computer search for it by analyzing the existing fragments for a pattern.
As soon as it spits out the result, Gul Ocett turns on them. She retreats to her ships, disables her erstwhile allies, and takes off towards Rahm-Izad.
Which is the wrong system. Ocett apparently made a botched attempt to subvert the Enterprise's defenses, so Picard and Nu'Daq were prepared for her betrayal and decided to turn the tables by giving her a false lead. Nu'Daq's engineer wasn't quite on the ball and let some damage through, putting his ship out of the running as well.
Their real destination is the Vilmoran system, where they find one planet with trace amounts of organic lichen that promises to be the final piece. On the surface, the crew (plus Nu'Daq) are soon joined by a very annoyed Gul Ocett... and a party of Romulans, whose cloaked ship has been tailing them from the start. A Mexican Standoff ensues. While everyone is busy bickering over who gets the prize, Picard and Crusher surreptitiously scrape some fossilized residue into a container. Their tricorder puts the last piece into place, and then...
A recording plays from one of the billions-old race that created the puzzle. She gives a heartfelt (and somewhat ironic) speech congratulating them for coming together in a spirit of friendship to find their secret message, explaining how the various humanoids across the quadrant were seeded by them eons ago. The audience, apart from Starfleet, is clearly not pleased by their reward, and go right back to insulting each other as they leave.
It is a bittersweet conclusion for Picard. The discovery his friend had sacrificed so much for, including his life, has fallen on deaf ears. That is, until he receives a message from the Romulan commander, who says something rather unexpected in parting.
Romulan: Well then, perhaps... one day.
Picard: One day.
- Absent Aliens: Billions of years ago, the precursors realized they were alone in the galaxy, so they created every other race.
- Apocalypse How: The Klingons trigger a Class 6 on Indri VIII.
- Benevolent Precursors: The precursor aliens seeded life on multiple planets and left scattered clues hoping it would make the younger races work together.
- Big "SHUT UP!": Picard has to yell at the Klingon and Cardassian captains to make them stop arguing."mevyap! Enough!"
- Big "WHAT?!": Nu'Daq, when his incompetent Number Two is unprepared for the Cardassians' attack.
- Bittersweet Ending: Picard finishes Galen's work, but the Klingons and Cardassians completely ignore the lesson it teaches. The Romulans, on the other hand, are more receptive.
- Bribe Backfire: Nu'Daq tries to subtly bribe Data, who sees right through it.
- Cosmetic Award: The ancient aliens' program, far from any sort of advanced technology, is a simple message of congratulations to the humanoids for solving the mystery of their origin. Probably for the best, given how many phasers were being brandished at the time.
- Curb-Stomp Battle: The Cardassians think they pull one on the Enterprise, but Picard is ready for it.
- Death Equals Redemption: Galen apologizes for being harsh to Picard on his deathbed.
- Early Installment Weirdness: This is the only appearance of a female Gul in the Cardassian military. It's later established that there's a gender divide among Cardassian society, where men dominate the military and women the sciences.
- Either "World Domination", or Something About Bananas: A non-linguistic variant—Nu'Daq and Gul Ocett argue over whether the genetic program is a weapon, a power source, or a recipe for biscuits.
- Famous, Famous, Fictional: As two examples of historically famous archaeologic discoveries, Galen mentions the city of Troy on Earth and an undescribed alien location called Ya'Seem.
- Feed the Mole: When Geordi discovers the Cardassians' attempt to sabotage the Enterprise's Deflector Shields, Picard arranges for them to be given false information as to the whereabouts of the final genetic piece, and then has the Enterprise prepared to minimize the damage from the sabotage.
- Mexican Standoff: Involving the Klingons, Romulans, and Cardassians. Picard and Crusher put an end to it when they collect the final DNA sample and finish the program.
- My Species Doth Protest Too Much: Played with. Gul Occett is the only female in the Cardassian military shown in the entire franchise, and is more reasonable and less arrogant than the typical Gul, but it doesn't stop her from holding Cardassian interests above others and cheat.
- Early Installment Weirdness: The Cardassian military is later established as a male preserve, with women dominating the science area. Though this is never established as being forbidden by law or regulation, so there may be exceptions.
- No-Sell: Data completely tanks the headbutt that the Klingon captain gave him in anger after thoroughly trouncing him at Klingon arm-wrestling. And then explains the technical details as to why he was completely unfazed by the assault.Data: My upper spinal column is a poly-alloy, designed to withstand extreme stress. My skull is comprised of cortenide and duranium.
- Not So Different: The Romulan commander acknowledges this between his people and humans.
- One-Sided Arm-Wrestling: Nu'Daq challenges Data to B'aht Qul (Klingon arm wrestling). Data wins in .47 seconds.
- O.O.C. Is Serious Business: It's the captain from the xenophobic and isolationist Romulans who's most impacted by the message.
- Panspermia: The precursors seeded life in Earth and most other inhabited planets.
- Pardon My Klingon: Nu'Daq does this a lot. So does Picard at one point.
- Plot Hole: So, why exactly did the Yridian ship explode so easily? According to Memory Alpha, there was line scripted for Data that was cut which explained that it was overloading its power generators and this combined with the phaser blast caused it to explode. Though even in the script it wasn't explained why they were overloading them.
- "The Reason You Suck" Speech: Professor Galen gives Picard one for staying on the Enterprise instead of joining him.
- Turns into Parting Words Regret when Galen is killed by the Yridians.
- Retcon: The episode is basically a giant excuse for the Trek franchise's multitudes of Rubber-Forehead Aliens, with very few species outside that shape.
- Rocks Fall, Everyone Dies: Occet comes close to invoking this before Picard and Crusher complete the genetic program.
- Screw the Rules, I'm Doing What's Right!: Picard blows off a Peace Conference to finish Galen's work.
- Survivor's Guilt: Picard briefly feels it for not going with Galen.
- The Worf Effect: It's a different Klingon this time, but Nu'Daq shows us just how physically superior Data is. Data immediately trounces him in arm-wrestling with no apparent effort whatsoever, then he tries a head-butt only to be somehow thrown back a few feet while Data doesn't even flinch.
- Worthless Treasure Twist: The result of the episode-long chase isn't a weapon or a power source, but a message from the beings responsible for humans and humanoid aliens. The Klingons and the Cardassians are not pleased.
- "Yes"/"No" Answer Interpretation: When Picard tells Nu'Daq and Occet that he knows they're both trying to complete Galen's genetic research, neither one of them says anything, which Picard takes as a confirmation.