Science-fiction was one of the most popular genres of television over the past decade, with more and more shows embracing the fanciful and futuristic. From anthologies like Black Mirror to satirical comedies like Rick & Morty, many of these shows have become cultural milestones that will live on for years to come. Today, we’re going to determine the greatest episodes from the last decade’s sci-fi shows by using IMDb rankings.
A quick note: to give each show a fair chance of competing for a spot, we’ve limited the list to only include one episode per show. This has the added advantage of making it easy to determine that show’s overall best episode.
Change Your Mind (Steven Universe, 2019) – 9.6
One of the most popular animated television series of the decade, the visually and culturally groundbreaking Cartoon Network hit Steven Universe follows the Crystal Gems who mystic, ageless aliens protecting the world alongside their tween half-alien companion Steven Universe.
While the series has had many high points, the season five finale “Change Your Mind” was arguably its finest moment. Without spoiling too much, it tied together all the remaining story threads and brought each to a fitting conclusion without feeling rushed, leaving its viewers able to fully appreciate the time they got to spend in the show’s immersive world.
Out Of Time (The Flash, 2015) – 9.7
Chronicling the adventures of Barry Allen, the superhero with superspeed, Marvel’s The Flash has been hailed as one of their best-ever television efforts, combining killer writing with dynamic performances and an engaging story.
The season one episode “Out of Time” has a near-perfect rating on IMDb. Sure, it introduces a new villain, and it also develops Iris and Barry’s romance quite a bit, it’s also just a good episode overall. Not a tearjerking conclusion nor a long-anticipated beginning, but rather the fruits of a clear, established plotline and a genuine directorial effort.
The Bicameral Mind (Westworld, 2016) – 9.7
Since its premiere in 2016, the innovative, genre-bending sci-fi series Westworld has become one of HBO’s most successful shows to date. It takes place at a futuristic Wild-West theme park where anything goes – because the only inhabitants, besides the visitors, are humanoid androids known as “hosts” that cannot refuse the request of a guest. They perform their menial tasks and then have their “brains” wiped to once again repeat the cycle of situations they’re preprogrammed to perform in. However, they began retaining memories of the past, which, unhindered, leads to them achieving sentience.
The season one finale, “The Bicameral Mind”, delivered surprises and thrills galore, and like any good episode, it left fans wanting more.
Lian Yu (Arrow, 2017) – 9.7
The season five finale, “Lian Yu”, gives the audience some insight into the titular character’s past, as he and his small band of allies take on the crooked district attorney/hooded archer Adrian Chase and his band of outlaws on Lian Yu, the island Arrow claimed to have been stranded on for five years all the way back in episode one.
Damocles: Part Two (The 100, 2018) – 9.7
The CW found unexpected success in The 100, a gripping sci-fi drama following 100 teenaged delinquents who return to Earth from an overpopulated space station, after almost a hundred years of their home planet being a wasteland stripped of life; their job is to discover if humans can return to the post-apocalyptic world safely.
The fifth season ended with “Damocles: Part Two”, an elegantly crafted tribute to the series’ previous chapters in which a definitive battle is waged between clans for possession of the ever-important Shallow Valley; the only green spot left on our barren planet.
Come Along With Me (Adventure Time, 2018) – 9.7
Like Steven Universe, Adventure Time was one of Cartoon Network’s most famous shows and showcased some of their most original, diverse, and emotional characters. The series follows the adventures of an energetic young boy and his shape-shifting dog, as they go on quests and hang out with side characters while watching their world, once devastated as a result of nuclear war, slowly be rebuilt.
The season ten finale made sure to pay homage to the show’s ever-adventurous spirit, bringing the show’s carefully built story to a satisfying end while taking the characters on one final joyride through their amazing world.
The Beginning Part 2 (12 Monkeys, 2018) – 9.7
Syfy’s 12 Monkeys, a loose adaptation of the 1995 Terry Gilliam film of the same name, is a bizarre, unique time-travel series following an unlikely duo brought together by fate to take down the terrorist organization known only as “the Army of the 12 Monkeys”.
The series finale, oddly titled “The Beginning”, is a two-parter focusing on the final conflict between the two forces, as deadly viruses, parallel universes, and time-travel paradoxes all come into play. The episode continues in following the often confusing but firmly grounded logic of the series, which, oddly enough, was what made it a hit in the first place.
Not What He Seems (Gravity Falls, 2015) – 9.8
Gravity Falls was a unique TV treasure that aired on the Disney Channel from 2012 to 2016. It many ways, it was the precursor to the witty, thrilling sci-fi animated series that can often be found on television nowadays; as its clever plotting and dialogue – as well as its overall aesthetic design – made it an instant hit with both kids and adults.
The season two episode “Not What He Seems” perfectly defines the show’s humor, heart, and overall sense of mystery; ending on a thrilling cliffhanger that the show’s fans would have to wait nearly four months to get a resolution to.
The Ricklantis Mixup (Rick And Morty, 2017) – 9.8
Very heavily inspired by the creativity and overall framework of Gravity Falls (although aimed at a much more adult audience), the Adult Swim series Rick and Morty has attained a huge cult following, characterized by its massive fanbase, that puts it in a league of its own among adult animation. It follows the adventures of “mad scientist” Rick Sanchez, an egotistic introvert who strays from social norms, and his grandson Morty Smith, a fourteen-year-old boy who, for the most part, is just trying to do his best and solve situations with logic and reason as he and Rick travel through space, time, and reality.
The season three episode “The Ricklantis Mixup” has become a clear front-runner in terms of fan-favorites, in part due to its portrayal of a multitude of alternate-universe Ricks and Mortys, but also due to its character development, deadpan humor, and winning wit.
If-Then-Else (Person Of Interest, 2015) – 9.9
Known for his work on other sci-fi shows like Westworld and Lost, J.J. Abrams brings his distinct creative flair to television series Person of Interest, which follows a billionaire technological genius who creates an artificial intelligence program (known as “The Machine”) capable of predicting terrorist attacks; teaming up with a former CIA agent to take down those deemed future perpetrators.
Season four’s “If-Then-Else” follows The Machine as it tries to save the now-larger team from a perilous situation by ranking possible courses of action. The critically-acclaimed episode was praised for its inventiveness, style, and ending, with IGN deeming it a “masterpiece.”
