Star Trek: The Next Generation is considered among some fans of the Star Trek franchise to be the most prominent representation of all its best qualities: friendship, adventure, tolerance, and intellectual curiosity. It’s said to exemplify the best in Star Trek storytelling, with some of the most beloved characters in science fiction. But even for all its accolades, there is a price to be paid for writers and creatives that boldly go where no one has gone before—some storylines just aren’t going to pan out.

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Due to its episodic nature, and the combination of writer changes and creative differences, Next Generation sometimes introduced plot devices or characters that, though incredibly important to their episode, were never featured again. Some are as innocent as not fully explaining an entity’s purpose, but some seem particularly important to remember.

Updated on September 18th by Derek Draven: We've added 5 more unresolved TNG storylines which continue to leave fans in limbo after so many years. Perhaps one day the answers will come, but for now there's precious little to go on, so fans may only speculate.

Ardra & Picard

Picard met his match in the season 4 episode Devil's Due when a career criminal posed as Ventax II's cultural equivalent of Satan. By playing upon the planet's fears regarding a long-prophesied return of the dreaded Ardra, she nearly succeeded in claiming the entire planet for herself.

Eventually Picard learned that the imposter utilized a bag of technological tricks involving transporters and holographic emitters to simulate her supposed powers. She was taken into custody by the Ventaxian government and vowed to cross paths with Picard again, though it never happened.

The Fate Of Ensign Ro Laren

Ensign Ro became a fan favorite late into the series, but it was clear she was never designed to be a regular cast member. Actress Michelle Forbes did not want to commit to a syndicated TV series, and by the end of the show's run, her character was written out.

Her disappointing decision to join the Maquis terrorist group sent her character out in disgrace, and she was never seen again. Forbes also turned down an offer to reprise the character full time on Star Trek: Deep Space Nine, but again refused, which prompted the creation of Kira Nerys as a replacement.

Picard's Irumodic Syndrome

Jean-Luc Picard is no stranger to physical afflictions. As a child he suffered from Shalaft's Syndrome, a hyper-sensitivity to sound, and in his advanced years he would develop Irumodic Syndrome, a variant of Alzheimer's disease. This particular affliction struck Picard in an alternate timeline comprised by Q as a final test of humanity, but it seems plausible that he was susceptible to it in the standard timeline as well.

The 2019 Picard spin-off series again references a chronic condition in which he confirms he was "was told a long time ago that it might cause a problem eventually." This may or may not be Irumodic Syndrome, which means this particular plot thread remains up in the air for discussion.

Captain Montgomery Scott

Mr. Scott graced the TNG series after the Enterprise found his crashed ship against the hull of a massive Dyson Sphere which he had been researching. Upon retrieving his pattern from the Transporter Buffer, he aided the Enterprise-D in further study (and escape) of the Sphere.

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With 80+ years of catching up to do, Mr. Scott left the Enterprise to pursue another adventure. What became of him is anyone's guess, as his character was never given a wrap-up in the same way that Spock was.

Commander Sela's Story Arc

After Denise Crosby exited The Next Generation just prior to the end of the first season, the actress made several cameo appearances in subsequent episodes before signing on as occasional character Commander Sela, the daughter of Yar and a Romulan male.

After several botched attempts to advance Romulan expansion into Federation territory (most notably a push to invade Vulcan), her character disappeared from the series altogether. Future Star Trek novels kept her character arc going, but as far as the TV space goes, the showrunners missed an opportunity to carve out a unique storyline.

The Experiments Of The "Schism" Aliens

Schisms - Star Trek: The Next Generation

Imagine going to sleep not knowing that alien beings were experimenting on you while you dreamed? The Enterprise crew initially has no idea they’re the victim of nocturnal medical experimentation in “Schisms”, and the creatures only leave once they begin to suspect something’s wrong.

These interdimensional beings never return to The Next Generation, so viewers (and the rest of the crew) don’t get to find out why they were experimenting on the Enterprise crew in the first place, or what they were doing with the data they collected. Starfleet never finds out anything about them after their first and only appearance.

The Conspiracy Parasites

Conspiracy - Star Trek: The Next Generation

When the senior staff of Starfleet have their minds taken over by a multitude of alien parasites, it makes for a gripping and unsettling episode in TNG’s first season. Captain Picard and the rest of the Enterprise crew have to find a way to stop the creatures from infiltrating the entire Federation and corrupting it from within.

At the end of the episode, the crew discover that the parasites managed to send a message to their homeworld, telling them to head to Earth. Obviously this would have been devastating, but the cliffhanger turned out to lead nowhere, and the parasites never featured again. Did they make it to Earth? If so, why didn’t Starfleet say anything?

Wesley Crusher & The Traveler

When Star Trek fans found out that “Journey’s End” would be the last episode to feature Wesley Crusher, they were elated. The boy wonder that had been featured as an honorary Starfleet member (prior to schooling) and given responsibilities far beyond his years by Captain Picard had become a nuisance on TNG. Much of his accomplishments felt undeserved, and the storylines he was a part of were some of the least compelling.

He followed an extraterrestrial being called the Traveler, who promised to reveal to him all of the secrets of the cosmos. Despite leaving the Enterprise and setting off with the Traveller, he was seen again in Star Trek: Nemesis and had rejoined Starfleet, leaving fans wondering why he’d given up on his journey.

Warp Speed Limits

The Enterprise at warp - Star Trek

Sometimes, introducing storytelling elements into a narrative doesn’t pan out on Star Trek. Its episodic nature and changing writers almost ensure that not every plot device brought up will see a satisfying conclusion. But certain elements that are designed to be logical rules inherent to the series' universe seem like they should be given more strict attention.

In the last season of TNG, Starfleet command puts a cap on the speed at which starships can travel. Anything beyond Warp 5 seems to tear apart subspace, possibly leading to the collapse of the universe. This “Warp Speed Emergency” cap only seems to last a few odd times, but it was eventually forgotten about and not used on any of the other Star Trek series of the time.

Q's Relationship With Guinan

Whoopi Goldberg at Guinan on Star Trek: The Next Generation

Q was an all-powerful, omnipotent cosmic being that toyed with the fate of his human friend Captain Picard on a whim, often using elaborate tricks to impart some sort of life lesson to him and the crew of the Enterprise, much to their dismay. Able to visit any time period and enter any dimension, there was little that could intimidate him.

Yet in “Q Who,” he reveals that he’s afraid of Guinan, the sagacious bartender on the Enterprise. She’s an El-Aurian with certain abilities herself, but nothing on par with Q. He implies they have run into each other before, but nothing is revealed of their history, and nothing ever comes of it.

Worf & His Brother

The episodes involving Lieutenant Commander Worf and his family always offered a further look into Klingon culture, especially its emphasis on honor and personal accountability. In “Sons of Mogh,” Worf’s actions demanded his family house be stripped of honor, causing his brother Kurn to request that Worf take his own life to restore it. Worf would not, instead electing to have Kurn’s memory erased and provided a new identity.

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In the events that transpired later, Worf had his honor restored, and his family regained its place of privilege within the Klingon Empire. However, it’s never mentioned whether or not Worf sought his brother Kurn out to tell him and give him his memories back.

The Neutral Zone Outposts

The Romulans in the Star Trek: The Next Generation episode "The Neutral Zone"

Many episodes in The Next Generation involved settling interstellar disputes. The Enterprise was often called in to act as a moderator and peacekeeper between two disagreeing alien species. In “The Neutral Zone,” it looks into what group destroyed the outposts that hug the Romulan border.

The Romulans maintain the Enterprise/Starfleet is responsible, and the Enterprise maintains that the Romulans did it themselves as part of a conspiracy. Though the episode is resolved satisfactorily, viewers don’t actually find out who destroyed the outposts. The second season episode Q Who references the destroyed outposts directly when Data compares their destruction to the same kind that took place on a nearby planet, but the link is never fully realized.

The Romulans & Picard's DNA

Picard and his evil clone

The plot to Star Trek: Nemesis involves a clone of Captain Picard who leads a rebel faction against the Romulan Empire. This young man, named Shinzon, was given the initial purpose of being utilized as a covert operative within the Federation to eventually replace the real Picard at a certain stage.

What isn’t made clear is how the Romulans got Picard’s DNA to manipulate in the first place. Shinzon has an accelerated aging process, but even accounting for that, the timeline isn’t explained. The earliest point implies Romulan mischief prior to them exiting their isolation. Maybe it was sometime when Picard was a cadet, or at least early in his Starfleet career, and wasn’t famous at all. Why would they choose him?

The Crystalline Entity

The mass email about "blowing some crystal" ended up being really misleading.

When the Crystalline Entity was first introduced, it was seen as a behemoth cosmic being that resembled a snowflake drifting among the stars. It had the ability to use warp speed and devour things as large as planets. It wasn’t known to have consciousness, and Starfleet knew next to nothing about it.

The Enterprise wasn’t able to study it very closely and could never determine why it seemed to absorb life as it traveled through space. Its reason for being and the point of its journey (much less where it came from) were never mentioned, and then the Crystalline Entity was destroyed by the Enterprise (albeit unintentionally).

Spock's Political Movement

It was always a happy occasion when members of the original Star Trek series appeared on TNG. Doc McCoy was a 137-year-old Admiral at the time of the series, popping in to offer some avuncular advice. Scotty appeared for a time after being unfrozen from transporter stasis, and Mr. Spock needed rescuing while trying to instigate a political movement to unify the Vulcans and the Romulans.

He was set upon by the Romulan secret police, but with the help of Picard and the Enterprise crew, he and his movement survived. Viewers never found out whether or not the movement was successful, garnered further support, or was destroyed. The next time Romulus appeared on screen, it was in the Star Trek reboot movie, and it was blown up.

NEXT: Star Trek: 10 Storylines That Hurt TNG (And 10 That Saved It)