“Praimfaya” is episode thirteen of season four of The 100 and the season finale.
In the previous episode, “The Chosen”, Jaha had instigated a riot during the lottery to choose which of Skaikru would remain in the bunker with the intent of attacking the Grounders and forcing them out. Kane had managed to, unbelievably easily, talk him out of this plan, but to quell the riot they gassed the lot with the (non-lethal) gas that Jaha had planned to use on the other clans. Instead of holding a lottery to see who remains inside, Kane and Jaha have decided to use the list that Clarke had come up with in “The Four Horsemen”, so Abby is going to survive despite her wishes.
Clarke, Bellamy, Murphy, Emori, Monty, Harper and Echo (the last was exiled by Roan for cheating during the conclave in “Die All, Die Merrily” and barred from the bunker by Octavia in “The Other Side” and who had arrived curiously conveniently to help the others when they were attacked) arrived at the lab on Alie’s island. After losing the first rover, getting Raven back to the bunker in time is unlikely – they likely have too many people to do the journey quickly enough – and even getting everyone inside is not likely.
Clarke’s Nightblood is not a full protection from the radiation, although it does help, so it isn’t a great solution. The island’s bunker does not enough supplies for five years, so there is an alternative – use the rocket in the lab to get into space to the remnants of the Ark. There is not enough fuel to get down again, but they will have five years to figure out a solution, should they manage to survive.
The episode stars with Bellamy in the lab speaking to Octavia in the bunker over the radio, letting her know their plans. Octavia is feeling uncertain and doesn’t know what to do. Bellamy says she needs to become a leader and not just a fighter. In the middle of the conversation the radio goes down (probably due to the radiation), and before Clarke got a chance to talk to her mother.
In the bunker, Indra tells Octavia it’s time to lead, before the 1,200 people waiting for leadership turn to violence. Octavia says that’s pretty much what Bellamy said. Indra will help Octavia. As Octavia is speaking to all the rest in the bunker, noise is heard from overhead. Back in the lab, the others are watching as the death wave hits Polis until the camera goes down. The death wave is accelerating and is only 110 minutes from the lab – and they have to lift off 20 minutes before it hits or they will never manage it. They have a lot to do to get the rocket ready in that 90 minutes and that’s not the hard part. The rocket was designed to dock with Polaris (which was destroyed) not the Ark, so will need manually piloting in. Plus they have more people than it was meant to carry and even more problems. Should be a piece of cake then.
Recovering the oxygen generator from the lighthouse bunker is one task. Taking enough supplies to last until the algae farm is up and running to feed them is another. Clarke is concerned that her Nightblood is not going to keep her alive, because of the premonition that Abby had of Clarke dying from radiation poisoning in “The Tinder Box”. She is looking a bit pale. Clarke wants to make sure that Bellamy is ready if she dies.
Prepping the rocket (which is a six hour check at the best of times) is not going well either. Both life support and communications get damaged during the prep – and without communications they are apparently stuck. The ring is not active and the power needs turning on. Raven planned to do that remotely using the communications system. They can’t turn it on from inside either – because to get inside they need to be able to communicate with the Ark. Monty and Murphy, who are collecting the oxygen generator, run into problems as Monty had to expose his hands to the radiation in order to remove the generator from the bunker. Everyone is running really short of time – and Echo may be up to something (although not what might be thought).
With only minutes left before the death wave hits, will they be able to establish communications with the Ark, get the rocket ready and get everyone back in time? Having to hurry is certainly not helping matters. With time running out and limited resources, tough decisions have to be made. Apart from the very beginning, nothing is seen of the bunker, with the majority of the episode being concerned with the race against time to get the rocket running.
The very end is set 6 years and 7 days after the death wave hits and a brand new plot thread opens up for season five.