Sci-Fi TV Shows That Were Canceled After A Cliffhanger

The science fiction genre continues to thrill television audiences after more than 70 years, taking viewers to different worlds and exploring far-out concepts. However, just because the genre boasts rich storytelling potential and spectacle, it is, of course, not at all immune to the dangers of a sudden cancellation. In an era when even an early renewal order can't guarantee subsequent episodes, that means some sci-fi shows end on cliffhangers, never to be given a satisfying conclusion.

With the stakes often so high for sci-fi television, that makes these unresolved plot threads all the more frustrating for fans following a series and invested in the characters. From being stranded across time and space to fan-favorite characters faced with mortal peril, these cliffhangers threaten to overshadow a show's legacy. Here are the biggest television cliffhangers in the sci-fi genre that were left unresolved by cancelations from the studios or networks producing them.

The popular sitcom "ALF" feels like one of those shows that could only exist and thrive in the '80s, which it did, running for four seasons. The quirky show follows Gordon Shumway, a wise-cracking extraterrestrial who crashes on Earth and moves in with a middle-class family in the Southern California suburbs. Gordon is nicknamed "AL," an acronym for "alien life form," and tries to acclimate to his new life while keeping his presence a secret. This is made all the more complicated when ALF contacts the President, leading the commander-in-chief to order the FBI to track ALF down.

"ALF" is a weird show, a quintessential '80s sitcom that just happens to have a Muppet-like alien for a protagonist. This blend of suburban comedy and Muppet-inspired science fiction struck a chord with post-"E.T." audiences, becoming a hit for NBC. Though a fifth season was planned, dipping ratings caused the network to cancel the show with the cliffhanger of "ALF" being captured by the government in the series finale. Unlike most shows on this list, the cliffhanger was eventually resolved by the TV movie "Project: ALF" — released six years later.

Though some may bristle at the assertion that a "Superman" show is considered science fiction, the eponymous extraterrestrial hero arrived on Earth from a dying world; that's as sci-fi as it gets. The '90s live-action series "Lois & Clark: The New Adventures of Superman" retained that premise, emphasizing Clark Kent's (Dean Cain) romance with fellow investigative journalist Lois Lane (Teri Hatcher). After several fake-outs and false starts, the happy couple finally marries early in the fourth and final season.

Season 4 resolves the Season 3 cliffhanger reveal that an entire colony of Kryptonians secretly survived the destruction of Krypton. This leads to Lois and Clark discovering a Kryptonian baby in their home with a note claiming that they belong to them. Though a fifth season was initially contracted, "Lois & Clark" suffered from plummeting ratings and was canceled in May 1997, with the baby plotline never officially resolved.

As the "Terminator" movies struggled to find their way forward after 2003's "Terminator: Rise of the Machines," the franchise found new life on television. Premiering in 2008, "Terminator: The Sarah Connor Chronicles" ignored "Terminator 3" and instead served as a sequel to the acclaimed "Terminator 2: Judgment Day." Pursued by Terminators sent from the future, Sarah (Lena Headey) and her son John (Thomas Dekker) time travel ahead to 2007, joined by Cameron (Summer Glau), a Terminator programmed to protect John. As Sarah and John move to prevent the creation of SkyNet, the malevolent artificial intelligence leading the Terminators, they encounter opposition from both the present and future.

The second season introduced Catherine Weaver (Shirley Manson), another Terminator sent back in time to protect John from SkyNet. In the series finale, Weaver takes John into the future while Sarah remains in 2009 to dismantle SkyNet without her son. John finds himself in a timeline without Weaver, where people he knew from his past adventures don't recognize him at all. "The Sarah Connor Chronicles" was canceled the week before the release of "Terminator Salvation," a movie distributed by a rival studio, with John and Sarah's fate in the show a mystery.

Backed by executive producer Steven Spielberg and adapting a short story by Ray Bradbury, "The Whispers" came out the gate with serious clout. Premiering on ABC in 2015, the show featured a town where its children communicated with an invisible friend named Drill. As disturbing accidents occur around the children, FBI agent Claire Bennigan (Lily Rabe) investigates while her young son Henry (Kyle Breitkopf) begins speaking with Drill. Claire eventually learns that Drill is part of a group of visiting aliens who intend to abduct the children.

With time running out, the season finale concludes with Claire desperately throwing herself at the aliens in exchange for Henry. This rushed trade is accepted, with Claire vanishing as the aliens depart, leaving Henry and his father Sean (Milo Ventimiglia) watching, horrified. However, even Spielberg's support and the cliffhanger ending couldn't save "The Whispers." What became of Claire and the other children abducted was left open, with ABC canceling the series after its single season later in 2015.

The 2019 Netflix original series "The Society" had all the makings of a young adult, suburban spin on cerebral genre-driven mysteries like "Lost." Set in a small town in Connecticut, the show focuses on a group of teenagers who are left behind when the town's population suddenly disappears. After realizing that the outside world has similarly vanished, the teens begin to form their own self-governed community. As the mystery of what happened to the rest of humanity deepens, the teens learn they are trapped in a parallel universe.

"The Society" was well-received and earned a second season renewal from Netflix two months after its premiere. However, the COVID pandemic led to extended production delays and Netflix canceled several previously renewed series, including "The Society." The series ended with a return to the regular world, which memorialized the missing teens, unaware of what happened to them. This unsolved mystery effectively became a cold case with the series' cancelation.

The quirkiest of the CW's line of DC Comics adaptations was "Legends of Tomorrow," which premiered in 2016 and ran for seven seasons. With an offbeat, self-aware sense of humor, the show follows a group of misfit superheroes who form a team to protect the space-time continuum. Even as other CW DC shows steadily came to an end, like "Arrow" and "Supergirl," and did so with proper series finales, "Legends of Tomorrow" ended its seventh season with a cliffhanger.

In what became the series finale, the Legends are stranded in World War I while the mysterious time traveler Booster Gold (Donald Faison) steals their time machine. As Booster Gold is arrested in a different time by his superiors, superhero Sara Lance (Caity Lotz) tells her wife Ava Sharpe (Jess Macallan) that she's pregnant. The introduction of Booster Gold was intended to increase interest in the show and the prospects of a Season 8 renewal. Instead, the CW canceled "Legends of Tomorrow," disappointing its devoted fanbase.