15 Sci-fi Shows That Ended On Cliffhangers

The beautiful part about science fiction is that it allows us to dream beyond our own imaginations. However, there are some TV shows out there that not only ran with this concept - they took it to a different dimension. A sci-fi series done right is supposed to keep you guessing. It’s just that generally, a good rule of thumb is that when the show ends, you want to give the fans some sort of closure; something they can hang their hats on that won’t have them replaying the final moments of their favorite characters in their head like some terrible nightmare they can't wake up from.

Unfortunately, in this world (and apparently in many others) we can’t always get what we want. In these particular cases, we can’t even wrap our minds around what could be, because the show just...ended, leaving us dangling on the possibility of what was.

While it’s entirely possible that the old saying is true and that some things are better left unsaid, these are definitely not those occasions. Take a look back at some of the best sci-fi shows on television that STILL have us wondering what the hell exactly was going on there.

Here are 15 sci-fi shows we love that totally left us hanging…

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Summer Glau and Lena Heady in Sarah Connor Chronicles
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15 Terminator: The Sarah Connor Chronicles

Summer Glau and Lena Heady in Sarah Connor Chronicles

Fans of the film franchise loved Terminator: The Sarah Connor Chronicles, so its ending after a brief two-season run was a huge disappointment as it was. But this sci-fi series did more than merely just fade into the dark hole where cancelled shows go - it left us with one of the most infamous cliffhanger episodes of all-time. Just what was Catherine Weaver’s goal? Why did John Henry need that chip? What was the deal with future John Connor and Cameron? Will mother and son ever see each other again? Wait, his father and uncle are still alive? And, why the hell has no one even heard of John Connor in the future?

So many unanswered questions still keeps many fan theories alive. One thing is for sure, it’s a good thing they never ran with the catchphrase "I'll be back" for this one.

14 Dark Angel

Dark Angel centered on a bunch of genetically enhanced kids, known as Transgenics, and took place in a post-apocalyptic world. It starred Jessica Alba and aired at the same time when Buffy, Angel, and Charmed were all huge hits. Naturally, this series fit right in. But after only two seasons, Fox cancelled the show to make room for Firefly (which some might even argue met the same fate).

In the end, we would never find out if Max gets cured or what would become of her and Logan. We still had no clue what the whole Conclave storyline was about, or why Sandeman was so focused on Max. While some fans got a bit of closure with Max Allan Collins’ novel After the Dark (a follow-up to expand on the series), most of us were counting on the show’s final moments to shed some light on a few pretty important things. Instead, they just left us all in the dark.

13 Friday the 13th: The Series

Robey and John LeMay in Friday the 13th the Series

Despite what its title might suggest, this show had nothing to do with the Jason Voorhees-starring slasher films. No, this awesome series followed a couple of characters as they hunted down cursed objects that their uncle had sold from his antique shop after making a deal with the devil. Whoever would end up with the artifact would be given some otherworldly power, but (of course) it would come at a high price, and someone would inevitably have to pay with their life.

The premise alone leaves room for a bunch of unresolved plot lines, but the series itself stranded fans in total limbo. It was cancelled six episodes short of their normal season, leaving fans dying to know if our main characters Micki, Jack and Ryan would ever retrieve all those items or be able to save their uncle’s soul. You could say the show ended with a devil-may-care attitude, which while extremely unfair to fans, was oddly poetic.

12 Mork and Mindy

Mork and Mindy's final fate

Playing the lovable alien named Mork (from Ork) catapulted Robin Williams into stardom. The series was a spinoff from Happy Days, which ironically was the ending we had all hoped for Mork and Mindy. But due to its sudden cancellation, the three-part season finale that was supposed to take us into season five aired before the show’s final episode (which was actually filmed first).

When all was said and done, we got some bizarre mashup where the duo was pursued by an evil alien, Mindy’s home got blown up, Mork’s alien secret was exposed to the world, and the two wound up lost in time. The actual final episode that aired didn’t even mention any of that. It just had Mork writing a report about being happily married on Earth in order to get a promotion. So, what really happened to Mork and Mindy? The truth is, we’ll nanu-ver know.

11 Sliders

Sliders Cast Season One

Sliders was a show with an intriguing concept that had a full five seasons to develop, and it had great potential for more. The series centered around a group of people “sliding” through parallel universes, hoping to return to their original Earth. They had no control over where they’d end up, but in these alternate Earths, they had a specific amount of time to right certain wrongs before heading back into the vortex which would then take them to the next parallel universe.

In season five, the series had lost one of its main characters (Jerry O'Connell), which didn’t make viewers too happy. The final episode of the series rocked what was left of the show’s devoted fans when a psychic makes a prediction that the group will die on their next slide. Rembrandt (one of the show’s other main characters) takes the leap, only for the psychic to die of a heart attack before Rembrandt could make it back. Apparently, like the psychic, we still have no idea what happened next.

10 John Doe

If the title didn’t give it away, John Doe was about a man who wakes up on an island off the coast of Seattle and seems to have no idea who he is. The short-lived series that only lasted one season just barely scratched the surface of this mystery man, who seemed to have the answer to an indeterminable amount of knowledge tucked away in his mind. As the savant helps the police solve crimes he digs deeper into finding out more about who he actually is.

Dwindling ratings led to the show being replaced (incidentally, by another short-lived series) which unfortunately left fans with way too many questions. In the last episode, we found out that it was John’s good friend who had been spying on him but the one BIG answer we never got was John Doe’s actual identity. Yup, you could say that sort of defeats the purpose of the entire concept.

9 The Dead Zone

dead zone tv -cast

After the Stephen King novel and the 1983 movie starring Christopher Walken, The Dead Zone TV series came back strong in 2002 with a built-in fan base. It revived the character of Johnny Smith (as well as Anthony Michael Hall’s career) and a new generation was introduced to the man who woke up from a six-year coma, who with a single touch could see the past as well as the future.

While Johnny was off solving crimes, dealing with his family’s new life, and having apocalyptic visions of the future, six seasons went by before the show was cancelled, leaving distraught fans without so much as a proper finale. It wasn’t until the very last episode when we find out that his father is actually alive, that his own son might share his gift, and that the Armageddon he envisioned was something he might have triggered. Turned out, Johnny’s last vision of a nuclear apocalypse really was the end of the world. Well, at least for the fans of the show it was.

8 The 4400

When 4400 people mysteriously reappeared after having been declared missing (each for a different amount of time), the world didn’t know what to make of it. None of them had any memory of what happened while they were gone, and not one of them had aged. They had all been returned with special abilities, however, and would soon become known as The 4400.

Eventually, it was revealed that they were actually abducted by future humans who chose them and brought them back with these gifts in order to prevent a major catastrophe. Right before the show went off the air, average people had started gaining access to Promicin, the drug that gives anyone a chance to live with superhuman powers (like The 4400), though it came with the small side effect of potentially killing you. Once more people began developing powers, they formed a militia, took over Seattle, and renamed it Promise City. We never actually found out what happened next. In a flash, as quickly as The 4400 arrived, the series was gone.

7 Invasion

invasion tv - cast

Invasion was about aliens who travel via hurricane, invade Earth, and (through a cloning process) start taking over people’s bodies. The show has been compared to be classics like Invasion of the Body Snatchers.

In the final episode, "The Last Wave Goodbye," the hurricane picks up, and two of the show’s main characters, Tom and Russell, work on a plan to keep the hybrids from taking humans. The other characters: Dave, Larkin, Jesse and Rose, are taken hostage, and in a failed attempt by Tom and Russell to rescue them, Larkin ends up getting shot. Tom makes the decision to put her in the water, essentially handing her off to the aliens in hopes of saving her.

So, did it work? We’ll never know. The show was cancelled before we could find out.

6 Reaper

Reaper Cast

College dropout Sam worked at The Work Bench (similar to The Home Depot) with his friends and the love of his life, Andi. But on his 21st birthday, he finds out that his parents had sold his soul to the Devil, and he must now become a “reaper,” tracking down souls who’ve escaped from Hell in order to return them to the Devil.

Each episode was filled with supernatural goodness, and the underlying mission was always about getting Sam out of his contract. But in what turned out to be the last episode, Sam’s plan to get out of his deal fails, which prompts Andi to offer up her soul in exchange. Thanks to a Demon turned Angel who claimed to have orchestrated it all under orders from above, the Devil now owned both of their souls.

Unfortunately, we still have no idea what those orders were or if they ever got out of their contracts. The last thing we see is Sam and Andi standing in parking lot with a confused look on their faces.

5 Flash Forward

This show had an awesome premise, but unfortunately, it only got to run for one season. Flash Forward centered around an event in which every person on Earth blacks out and awakens with visions of their future. While the series finale did affirm that some of the flash forwards came to fruition, we never actually found out what the worldwide blackout was all about, and what the meaning of it all was.

In what could be considered one of the most aggravating finales in TV history, knowing that the creators had planned for more seasons, they left viewers hanging with a second global blackout, a weird montage, and then a building blowing up with one of the characters still inside. Too bad fans didn’t get a glimpse of the show’s future ahead of time. That might’ve been helpful.

4 Alphas

The Syfy show about a team of "Alphas" with enhanced powers tracks five people who investigate crimes committed by other “Alphas”, who have superhuman capabilities of their own. In two seasons, this clever series drew fans in with a great cast and exciting storylines. But, as the golden rule of TV ratings goes, once viewership numbers went down, so did the show.

The series finale, however, set the bar pretty high when it comes to cliffhangers. By the time all was said and done, the team couldn’t stop the generator from going off, and it left everyone lying flat in Grand Central Station (at least we think that’s the extent of the damage). The only one who wasn’t affected was one of the main characters, Gary, whom we see just stepping over everybody - including his friends and oh, the bad guy. Were they even still alive? Who knows? Maybe someone should ask Gary, who according to the show (and Simon & Garfunkel), was “The Only Living Boy in New York.”

3 Revolution

revolution tv - cast

With Eric Kripke and J.J. Abrams at the helm, everyone had such high hopes for this show. Kripke had just come off Supernatural and Abrams, well, it’s possible that the writing was on the wall with the finale of Lost, but we had hope there nonetheless.

The show takes place 15 years after a global blackout where life has slowly started to return to the world prior to the industrial revolution. Unfortunately, with only two seasons, there would be no proper ending, and fans were left with a ton of unanswered questions. Not only was there very little closure, but they actually left you dangling, as if they were coming back for a third season. In the end, the nano would find new hosts and the President, Ed, and Tom are ordered to go to Idaho, where apparently some other people were living. But hey, at least no one died.

2 The Bionic Woman (2007)

Michelle Ryan in The Bionic Woman

In 2007, NBC brought back the 1970s smash hit with the same title, but this time, the character of Jaime Sommers was a bartender who ended up receiving bionic parts (from her surgeon boyfriend) after a car crash nearly took her life. However, as a victim of the 2007-2008 strike by the Writers Guild of America, The Bionic Woman only lived to see eight action-packed episodes. Not only did we not have any clue what would happen with Jaime’s five-year life expectancy, but after some trust issues with her partner leads to Antonio’s death, the last episode that aired puts Jaime in a situation where she’s ordered to act as an assassin for the very-first time.

Leaving us dangling mid-season like that was a huge sci-fi tease wasted on a show that had a ton of promise.


Alf eating an ice cream cone

Children of the ‘80s grew up watching the lovable alien called ALF from the planet Melmac adapt to life on Earth, hiding out with a sweet middle class family (the Tanners). For four seasons, families sat around their TV sets together and watched the wise-cracking puppet-like alien bond with the family over a few jokes and what was always an important moral to take away after each episode - except, of course, for that last one.

In what was perhaps one of the cruelest cliffhanger finales in television history, the show wrapped up with ALF getting busted by the Alien Task Force. The last thing we see is him being taken away to be dissected (among other things). The cliffhanger ending (which was only intended to bookend the season, not the series) was so bad that they even made a TV movie years later called Project ALF, which sadly was even worse. In it, ALF is still alive but never reunites with the Tanners. He doesn’t even remember them. For some weird reason, they moved to Iceland.


What are some of your favorite sci-fi shows that shocked you with their crazy cliffhangers? Let us know in the comments!

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