[This is a review of the The 100 season 4 finale. There will be SPOILERS.]
Since the series premiered, The 100 has always been a story of survival, and the lengths to which people will go to save mankind from extinction. In season 1, that theme was represented by the inhabitants of the Ark space station, whose leaders sent 100 underaged criminals to the surface of the Earth to test the planet's habitability following a nuclear storm. Since then, surviving on Earth has become even more difficult with the introduction of the Grounders, who were split into 12 different clans and served only the interests of their own people.
For its part, The 100 season 4 premiere introduced the threat of Praimfaya, another nuclear holocaust that will destroy anyone exposed to the radiation death wave. Much of season 4 has seen Clarke, Bellamy, the leaders of Skaikru and various other clans fighting for a way to either protect only their people or, in moments of hope, all of the clans. As of last week's penultimate episode, 'The Chosen', the only means of survival was a bunker under Polis that could house 100 people from each of the 13 clans (with Skaikru as the thirteenth clan). However, Clarke and her friends devised one other means of the survival: The remnants of the Ark that was still floating in space.
In this week's season 4 finale of The 100, 'Praimfaya' -- written by showrunner Jason Rothenberg and directed by Dean White -- Octavia attempts to keep order in the bunker as those protected are forced to wait out the death wave of radiation. Meanwhile, Clarke, Bellamy, Monty, Raven, Harper, Murphy, Amori, and Echo prepare to launch themselves into space and make the Ark hospitable for themselves to wait out the nuclear apocalypse created by Praimfaya on Earth.
'Praimfaya' starts off with an emotional conversation between Octavia and Bellamy after the latter has informed the former of their plan to stay alive by traveling up to the Ark. Their relationship had been rocky at the start of season 4 due to Bellamy working with Pike in season 3 (the man who killed Lincoln) and Octavia struggled both to forgive her brother and deal with her grief over Lincoln. However, 'Praimfaya' sees Octavia assume the role of commander of those who were chosen to live in the bunker beneath Polis. Octavia worries that she isn't able to take on the important leadership position at such a crucial point in humanity's fight for survival, but thanks to the support of her brother - who she's finally fully reconciled with - and Indra, the girl who was raised under the floor steps up to lead.
Beyond Octavia's decision to take on the role of commander, and her motivational speech to those within the bunker, we don't see what becomes of the chosen people. Octavia ends her speech with the saying of the religious group that created the bunker: "From the ashes, we will rise." However, since the safety of those in the bunker has been seemingly assured, The 100 season 4 finale shifts focus away from them. After Octavia's speech, those at the lighthouse watch the death wave hit Polis, but that's the last we see of the bunker. Considering there doesn't seem to be much conflict left within the bunker - since Octavia is their leader and the decision has been made about who will survive - it makes sense for The 100 to conclude this storyline early in the finale.
Instead, 'Praimfaya' focuses entirely on Bellamy and Clarke's group as they struggle to get the rocket ready in time to launch before the death wave hits the lighthouse. Just like any kind of conflict on The 100, the odds are stacked against the heroes and, predictably, not everything goes according to plan. Between the communications system on the rocket breaking down entirely, Monty sacrificing his hands to the radiation to get the device they need for oxygen on the Ark, and Echo trying to kill herself, plenty goes wrong for Bellamy and Clarke's group. However, these conflicts help to ratchet up the tension in 'Praimfaya', and with the threat of death by radiation hanging over the heads of some of the most compelling characters, The 100 achieves a fast-paced and exciting finale.
Of course, 'Praimfaya' wouldn't be a season finale of The 100 if Clarke wasn't forced to make some kind of massive decision and/or sacrifice. In the case of season 4, that winds up being Clarke deciding to stay behind to make sure the ground satellite is lined up with the Ark so that the power gets turned on and her friends can survive. It's a much different sacrifice than those Clarke has made in previous seasons, which largely saw her sacrificing others for the sake of those she loves. But, with season 4 examining the selfish vs selfless nature of Clarke's sacrifices, her choice to stay behind is a fascinating turn for her character.
Still, while The 100 excels at creating tension by forcing its characters into situations that seem impossible to survive - and the threat of death actually hangs over their heads since the show is willing to kill off important characters - the series also succeeds in grounding the events in compelling character drama. Bellamy portrayer Bob Morley especially has a great deal to work with in 'Praimfaya' between his character's conversation with Octavia and various discussions with Clarke. He and Clarke have been through plenty together as essentially the co-leaders of the original 100; Bellamy has often shared in Clarke's decisions and sacrifices, like helping her defeat the Mountain Men in season 2.
As such, Clarke's decision to stay behind leaves Bellamy to lead those aboard the Ark on his own, for the first real time without Clarke. Leading up to that point, Clarke and Bellamy have a couple conversations about what they've been through, with Clarke giving him the same support to become a much-needed leader as Bellamy gave Octavia earlier in the episode. The dynamics between the teenaged characters has always been a strength of The 100 and 'Praimfaya' capitalizes on character arcs for Clarke, Bellamy and Octavia that were first established in season 1, giving the season 4 finale a kind of full circle feel.
In terms of the actual events of 'Praimfaya', the episode also sets the stage for an essential reboot of the series. In the final sequence of the season 4 finale, The 100 sees a six year and seven day time jump that finds Clarke on the surface of the Earth, which has started to recover from Praimfaya. Clarke sets up a small satellite and tries to make contact with Bellamy aboard the Ark - something we learn she's done every single day since Praimfaya - though she's not sure if he actually receives her message. Clarke's message acts as a kind of epilogue to the season as she questions why Bellamy and the others haven't returned to Earth from the Ark even though the planet has been habitable for over a year. She also reveals she couldn't dig her way into the bunker because there was too much rubble.
This sequence additionally reveals Clarke has been taking care of a young nightblood named Maddie, and they witness the descent of a spaceship that is designated as a prison transport vehicle. It's a cliffhanger that offers many more questions than answers for The 100, and sets up a fifth season that will no doubt look incredibly different than all the preceding seasons. With the fates of Bellamy, Octavia and those in their care unknown, it remains to be seen how exactly The 100 will progress from here, but fans of the series can certainly expect more explorations of the theme of survival as its characters are forced to contend with new obstacles in season 5.
The 100 will return for season 5 on The CW.