WARNING: The following article contains spoilers for the first five seasons of The 100.

This week, The 100 returns for its sixth season on The CW. Loosely adapting the sci-fi novel series of the same name by Kass Morgan, the television show has amassed a dedicated legion of fans tuning in to watch the ongoing adventures of the last remnants of humanity as they struggle to survive and rebuild civilization after a nuclear apocalypse consumed Earth. It's easily The CW's darkest, grittiest series currently on the air, and doesn't pull its punches in terms of content.

With 71 episodes across its first five seasons, it's a tall order for those who've never seen an episode to binge the entire series in time for the Season 6 premiere, so here's a quick overview of the popular post-apocalyptic show and the story so far.

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What's the Deal with This Show?

Beginning 97 years after a nuclear apocalypse triggered by a rogue artificial intelligence wiped out the vast majority of humanity and rendered most of the planet uninhabitable, survivors have taken refuge in a space station orbiting the Earth. As the population on the station grows unwieldy and the aging installation begins to feature technical difficulties, the leadership decides to send one hundred teens and young adults planetside guilty of various minor crimes in an effort to converse supplies while forming a tentative colony.

As the titular one hundred colonists undergo their own post-apocalyptic updated take on Lord of the Flies, trying to establish a sense of civilization in the lawless wild, they quickly discover different factions of surviving humans have thrived planetside in the interim time, each more dangerous than the last and not particularly welcoming of strangers.

Why Are a Group of Teens and 20-Somethings the Last Hope for Humanity?

As they grow accustomed to their new, harsh surroundings, the 100's de facto leaders are tough-as-nails Clarke Griffin and no-nonsense authoritarian Bellamy Blake. Other survivor characters include Bellamy's younger sister Octavia, tech-savvy Monty Green and Raven Reyes, and sarcastic John Murphy. As the group settles, they dub the other survivors surfacing on the surface as Grounders who are similarly full of young adult characters. As the series progresses and more older characters join the main cast, the show still predominantly looks to its young adult characters for leadership as they quickly come of age and adapt to the planet faster than their more mature counterparts.

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Also, it's a series on The CW. That means there's going to be a prominently young adult cast of characters that are in distractingly good physical shape and that listen to Imagine Dragons, because if there's one band that survives a nuclear apocalypse, it's them.

Why Can't Anybody Play Nice?

With the fate of the human race at stake, one would think the survivors would put aside their differences and attempt to build a brave, new world together. But, if The Walking Dead has taught audiences anything, it's that post-apocalyptic scenarios and the collapse of society bring out the absolute worst in humanity, which is very much the case here. From civilizations subsisting on human blood to forced cannibalism, the characters must endure escalating extremes just to survive.

In addition to having to live with each other, the Sky People or Skaikru as they become known by Grounders, form an extremely fragile peace with the Grounders that often descends into open, bloody conflict. And just as the Sky People find themselves at odds, there are rival clans of Grounders around the planet that experience much in-fighting themselves. In short, to paraphrase John Carpenter's The Thing, nobody trusts anybody now and they're all very tired.

What's the Deal with Clarke and Bellamy?

Even with the constant threat of death and complete annihilation of the species, the survivors of The 100 still find plenty of time for romantic entanglements and dangerous liaisons ostensibly to deal with the never-ending high stress scenarios and literal life-or-death decisions. Everyone is quite attractive and in tip-top physical shape somehow, so it's little surprise there is a surprising amount of sex on this show.

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One of the longest-running will-they-won't-they relationships revolves around its leads, Clarke and Bellamy. They've been dubbed "Bellarke" by the fans because, of course, the two initially had an antagonistic dynamic at the start of the series, with Clarke clashing against Bellamy's hardline efforts to keep the one hundred in tight, disciplined control to survive. Bellamy eventually softened his leadership style as the series progressed and the two became reluctant allies and eventually close friends and confidantes. While there have been hints that there could be something more between the two, Bellamy actor Bob Morley admitted there were "too many landmines" between his character and Clarke after five seasons together.

How Did the Earth Get So Messed Up?

After enduring a nuclear apocalypse, the planet faces additional threats as the nuclear reactors around the globe begin to fail after decades of neglect by Season 4. Facing an incoming radioactive storm that will engulf the planet for over five years, twelve clans including the Sky People each select one hundred people to take cover in a large bunker while others return to space, with the inhabitants of the bunker facing five years of hell as supplies dwindle leading to institutionalized cannibalism and gladiatorial death matches.

Following the nuclear storm, only one valley is left on Earth habitable by human life; conveniently near the bunker where much of the species took shelter. As the survivors attempt to rebuild after enduring the horrors of the bunker, a new faction of deadly prisoners held on a maximum security space station land on the planet leading to renewed conflict. As the fighting escalates, a doomsday protocol is initiated by one of the former prisoners targets the valley for complete obliteration by orbital missiles and render the planet completely uninhabitable.

What's Next?

The Season 5 finale had all the remaining humans on Earth take refuge on a spaceship before the valley's destruction and enter cyrosleep while Monty Green and his partner Harper observe the planet to see if it ever becomes capable of supporting human life. Over the course of several decades, they have a son named Jordan whom they put into cryosleep when he reaches adulthood to eventually join the others. After realizing that Earth will never recover, Monty plots a course for a distant planet capable of supporting human life, eventually dying of old age with Harper.

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In the final scenes of the Season 5 finale, Clarke and Bellamy emerge from cyrosleep with Jordan who introduces himself and shows them a video left by Monty updating them on the past several decades and bidding them good luck in a fresh start for civilization, away from the horrors they endured to survive on Earth the past several years. As the survivors begin to awaken, they must overcome the atrocities they committed against one another back home if they hope to survive this dangerous new world.

The 100 returns on the CW for its sixth season on April 30 at 9 pm ET/PT. The series stars Eliza Taylor, Paige Turco, Marie Avgeropoulos, Bob Morley, Henry Ian Cusick, Lindsey Morgan, Richard Harmon and Tasya Teles.