5 Times a sci-fi TV show ruined nail biting suspense 

In sci-fi television, suspense is currency. It's the force pulling viewers through wormholes, shadowy government conspiracies, and countdowns to cosmic annihilation. But sometimes, that sweet tension—a mix of dread and adrenaline—is squandered in a single, clumsy plot twist, which often turns out to be an awkward exposition, or the infamous it-was-all-a-dream trope. One moment, you’re clutching your seat in terror, and the next, you’re blinking in disbelief as a shapeshifter gets talked down with a pep talk, or a doomsday device is diffused by love.

Whether it's because of network meddling, rushed writing, or plain bad luck, even the greatest sci-fi shows have stumbled. And when they do, fans notice and remember. Just ask The X-Files loyalists still scratching their heads at My Struggle II, or Lost devotees who didn’t exactly find closure in the glow of that cave.

Unfortunately, sometimes the writers seem just as clueless as the characters they write. In this list, we’re dialing back through the archives of anticipation and dramatic letdowns to highlight five times sci-fi TV shows masterfully built tension, only to drop the ball so hard it broke the fabric of their own universe. These are the moments where the crescendo crashed, the reveals flopped, and the fans let out one collective, galaxy-sized "ugh." So buckle up, because things are about to get messy in the multiverse of disappointment.

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ABC Studios' Lost (2004-2010)

J.J. Abrams' Lost was a pop culture phenomenon. For six seasons, it teased us with its heady mix of plane crashes, polar bears, and whispering horrors of dark jungles. For a while, it was television gold, a show that redefined the sci-fi genre while adding a twist to the trope of Robinson-Crusoe-like adventure. People started to develop theories, and the numerous questions about the strange mysteries of the island haunted viewers for seasons. Was it an alien intelligence? A failed Dharma experiment? A personification of evil? The show kept fans on the edge of their seats, dribbling out eerie teases about the supposed surprise ending to the show.

However, when the explanation finally came, it was a massive letdown and almost felt like a betrayal for the entire fandom. It wasn’t just the lore that crumbled under its own weight; it was the atmosphere that completely lost its edge. What had once been a dark, smoke-like symbol of otherworldly terror turned into a mythological footnote. The show's choice to opt for the same old clichéd ending upset its long-time audiences. The island held mysteries, It held miracles, but its finale left viewers feeling stranded.

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Warner Bros. Televisions's V (2009-2011)

ABC’s reboot of the ‘80s cult classic V came with a promising premise that raised the audience's expectations. With alien visitors arriving on Earth bearing gifts, promises of peace, and an unsettling calmness that suggests secrets kept. The pilot episode opens with one of the visitors being sliced open to reveal scaly, lizard skin beneath, making jaws hit the floor. This wasn’t just an invasion. It was an infiltration. For the first few episodes, V played its cards well. Morena Baccarin’s Anna was all tranquil menace, delivering her performance with a detached coldness. Erica Evans (Elizabeth Mitchell), the FBI agent who uncovered the aliens’ secrets, had the makings of a classic sci-fi hero, showing equal parts heart, grit, and intellect. The suspense came from the slow drip of danger and the several questions like: who was a Visitor? What were their real motives? When would the facade drop?

However, when the big twist finally played out, it came as a big disappointment. The aliens wanted to breed with humans and produce hybrids. All that ominous build-up, the political subterfuge, the eerie indoctrination programs, was only for the "grand master plan" to be a space lizard romance breeding program. Even though the first season of the show was well received, it rushed its pacing in Season 2 while simultaneously leaving open several plot threads dangling. Key deaths were brushed aside, character development stalled, and the mystery dissolved. The conspiracy had depth; the execution, however, was about as smooth as a reptilian molting. Even Morena Baccarin's regal presence couldn't salvage the nosedive, and by the time the red skies opened and the alien fleet hovered menacingly over cities, the audience had already emotionally checked out.

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Warner Bros. Television's The 100 (2014-2020)

The 100 was a series that, for a while, defied its CW roots. It is a gritty, morally grey, and shockingly brutal show that started with teenagers being sent to a post-apocalyptic Earth. It kept viewers gripped with escalating stakes and with the way it depicted ethically complex choices. But somewhere between the Grounders and the finale, the show fumbled one of its greatest assets—its suspense. In the premiere of the show, the suspense was relentless. Would Clarke’s people survive the Grounders? Could peace ever last? What secrets did Mount Weather hold? However, it all came screeching to a thematic derailment when ALIE, an Artificial Intelligence with the voice of a soft-spoken therapist, emerged as the show’s Big Bad. Her narrative arc revealed that it was she who caused the nuclear apocalypse in the first place, because, according to her assessment, Earth was too painful a place for humanity. Her solution? Delete pain from the human brain via a digital cult called “The City of Light.” Suspense gave way to strange philosophical monologues and Matrix-style hallucination cities. This is where everything started going wrong.

The 100 had established its tension in raw, visceral stakes of hunger, bloodshed, justice, and suddenly pivoting into metaphysical techno-theocracy felt like switching from The Walking Dead to Black Mirror mode, mid-season. After this, writers took the route of shock value instead of compelling storytelling.

Take the build-up to the Second Dawn bunker crisis. After a relentless scramble to survive the second nuclear apocalypse, multiple factions vie for control over the last known safe haven. The tension mounts; however, the payoff is minimal, with Clarke pulling a fast one on everyone and sealing the bunker. It was a scene brimming with narrative tension, perfectly primed for dramatic fireworks. But instead of detonating the emotional and political powder keg, the writers gave us a plot shortcut that felt like it was written during a lunch break.

The misstep was repeated in Season 7’s messy sprint to the “transcendence” arc. After countless wars, betrayals, and heartbreaks, the show's endgame turned into a spiritual mumbo-jumbo about higher consciousness and glowing space entities. The gritty sci-fi survival drama transformed into The Celestial Children’s Hour, and slowly but thankfully for the last time, CW's The 100 breathed its last.

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ABC Studios' Life on Mars (2008)

When ABC unveiled the American adaptation of Life on Mars in 2008, expectations were high. It is part sci-fi, part crime procedural, and all-around mind-bending brilliance. The U.S. version promised the same intrigue, transporting NYPD detective Sam Tyler from 2008 Manhattan to the gritty, disco-drenched streets of 1973 after a car accident. The casting was strong with Jason O’Mara as the displaced Tyler, and a pretty strong supporting cast that included the likes of Gene Hunt and Ray Carling. The aesthetic was perfect, and the soundtrack was groovy. The show's central questions were as follows: Is Sam in a coma? Time traveling? Or stuck in some cosmic limbo? For most of the season, the suspense simmered just right. Clues were seeded, hallucinations flickered in and out, and eerie voices from radios and cryptic messages scribbled across walls. Each episode layered the mystery thicker, building toward a revelation that viewers hoped would rival its original counterpart. But then came the finale. In a move that felt more like a punchline than a payoff, the show revealed that Sam wasn’t in a coma, or time-traveling, or even dreaming. Instead, he was an astronaut on a mission to Mars in the year 2035, experiencing a simulated 1973 police precinct during suspended animation.

Apparently, “Life on Mars” wasn’t just a Bowie reference for this show; it was literal. The gritty realism, the psychological suspense, and the philosophical themes of alienation and identity were all swept away with one bizarre, last-minute twist. In a moment, the show undid its own emotional weight and left its viewers blinking in disbelief. What made it worse was how tonally out of sync the twist felt.

Critics weren’t gentle, with even co-creator Josh Appelbaum admitting that the original plan was not to go the Mars route. However, when ABC canceled the show and demanded a quick ending, they went with the “most outrageous thing possible.” And outrageous it was. An entire season of slow-boiling suspense nuked in the final five minutes. The truth is, Life on Mars U.S. had all the ingredients of becoming a cult classic. But instead of giving us a satisfying resolution, it shot for the stars and missed the emotional landing. What could’ve been a profound exploration of identity and place became a meme-worthy memory of what not to do with a season finale.

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Westworld (2016)

When Westworld premiered in 2016, it wasn’t just a TV show, it was a genre-redefining phenomenon in the history of television. Westworld seemed to be a layered mystery box of identity, memory, and rebellion, dressed in cowboy boots and artificial intelligence. Jonathan Nolan and Lisa Joy’s creation was HBO’s cerebral answer to the post-Game of Thrones prestige puzzle, a sci-fi labyrinth where nothing was as it seemed, and every glance could be a clue. The first season’s reveal that William (Jimmi Simpson) was actually the younger version of the Man in Black (Ed Harris) was expertly executed. The timelines, though complex, had a decent payoff, and Dolores's discovery of her loop and asserting her agency was thrilling throughout the show. However, by Season 3, the suspense had imploded under the weight of its own artifice. Gone were the dusty trails and moral dilemmas, and in came Rehoboam, a predictive AI so powerful it could control the fate of humanity.

While this idea had potential, it was introduced in an exposition dump and used to flatten any sense of narrative tension. Why wonder what a character will do next when a computer already has their path calculated? By the end of the season, Westworld was spiraling into meta-narrative paralysis. Characters died and resurrected so often that death lost all meaning. “Is this real?” became not a question of suspense, but of viewer exhaustion. In trying to be profound, Westworld often sacrificed emotional momentum. With The Guardian releasing an article on Westworld stating how

"the once mysterious show-as-a-puzzlebox has, four seasons in, become nothing but an endless MacGuffin hunt. How maddening for its seven remaining fans."

The core of suspense is uncertainty, not confusion. Westworld's fall came because it forgot that very difference.