Spoilers below up to 4×10, the rest is speculation based on interviews & episode descriptions.

There are a few things we know for sure about the finale: Jason Rothenburg has said the finale will be in real time, 44 minutes before the “Death Wave.” He’s also mentioned that fans would not have been satisfied with the ending had season 4 ended up being the series finale, suggesting a cliffhanger (ugggh!). Eliza Taylor herself said it’s her favorite finale to date and she thinks fans will “love it.” She also hinted that there may not be a lever for Clarke to pull this season and that this finale would set up next season in “different” ways then past seasons – perhaps meaning a time jump.

We also know the name of the last few episodes:

4×11: “The Other Side”– Possibly a reference to Jasper’s favorite line, “see you on the other side.” or perhaps the other side of the door of the bunker? or both? The official synopsis only says that Clarke will face the consequences of her decision. Pretty vague.

4×12: “The Chosen” – Possibly referring to those chosen for the bunker, the nightbloods, or the Second Dawn believers who reached level 12. The episode description says Clarke leads the delinquents to try to “save a friend” – Raven?

4×13: “Praimfaya” – obviously, the death wave. This will be a episode shot in real time, t-minus 44 minutes to the Death Wave

So, knowing all that, how could this season possibly end? Let’s flip through the choices:

Praimfaya is Stopped

There really only seems to be one predominate theory about how this may occur, and it has to do with Raven & Becca/A.L.I.E. First off, we have to discuss Becca/A.L.I.E. – which one is it? Raven automatically assumes she’s speaking to Becca, perhaps because of the laboratory coat. But this is strange. Becca was in A.L.I.E. 2.0, the flame that carries the souls of the Commander. A.L.I.E. 1.0, the end-of-the-world program, was not connected to the flame, instead it was already on Earth, where Jaha found it/her in the mansion, where it then was consumed by the population and uploaded them into the city of light. So, Raven has been ‘infected’ by the chip she ate, which is in no way connected to Becca’s soul/mind, it’s connected to A.L.I.E. 1.0. So, it doesn’t seem like Raven is talking to Becca, but season 3’s Big Bad A.L.I.E.What does A.L.I.E. have up her sleeve? Why does she want Raven to go into space in the rocket? Perhaps she has more in mind than a nice view while Raven dies. Some speculate that when Raven is in space, she will some how be able to stop the Death Wave. How? I have absolutely no idea (but we aren’t exactly dealing with real radiation science here). Perhaps something in the rocket is the key – and it has to be done in space. Another possibility is that while Raven is in space she will encounter the lost Asteroid Mining Penal Colony that has been mentioned very briefly the past two seasons. In 4×01, we see a newspaper headline on the screen behind Raven that reads, “Contact Lost With Asteroid Mining Penal Colony.” Why mention this colony in any capacity if it’s not going to be relevant? Perhaps, if they do do a 5 year time jump, the colony would have the technology to fix Raven’s brain! Or help with the death wave? The Bunker is actually used

So the bunker can hold 1,200 people. There’s a theory that Octavia will decide to let every clan choose 100 people (assuming Clarke’s attempt at stealing the bunker ends up failing) from their clan. 12 clans of the Grounders, subtract Floukru because they are all dead (RIP Luna), and add Skaikru = 1,200. Assuming something like that happens, where can they go from there? Plus it would give even more significance to the title of the show. But if they go this route, there are really only two paths they could take:A) Next Season is in the Bunker

I highly, highly, highly doubt this will be the case. An entire season in the same setting? Considering how big this show’s map usual is, I can’t imagine they would go this route. This show loves world building, and in a cramped bunker, it doesn’t sound like there would be much world to explore. It sounds incredibly boring. Next. B) Time Jump

There only other possibility is a 5 year time jump. Plenty of other shows have done it, like Pretty Little Liars and One Tree Hill – but would it work for The 100? Though I wouldn’t mind seeing our beloved delinquents a bit older than they are now, I’m not a fan of this route. A 5 year time jump is a huge risk for the show to take. Plus, considering character growth and development is vital to the show, a 5 year time jump would throw a wrench into that process. One interesting idea I saw floating around was that Clarke would be forced to stay outside of the bunker and separated from the rest of Skaikru for betraying everyone. She would survive as a nightblood (most likely) but it would be hella lonely! It’s possible they will take this route – but let’s hope not. The Hypersleep/Cryochamber theory

This is a very interesting theory: it’s going to require some mythology and screengrabs.So, clearly there is a connection between the Second Dawn and the Grounders. We know the tattoo on the Flamekeeper has the same symbol in the middle that is on the Second Dawn bunker key and inside the bunker itself. See below: So, we know the Grounders are both connected to Becca and the Second Dawn. But how? The prior, we know, the later, is a bit more mysterious. Some fans suggest when Becca first landed on Earth after the apocalypse, when she said, “I’m here to help,” she was specifically addressing the Second Dawn, because she knew about their cult (as it seemed people around the world did, considering it was on the news) and knew they would be alive. The Second Dawn symbol, above, is the symbol of the Flamekeeper’s “holy order” according to Gaia. So, if Becca did join the Second Dawn, perhaps they became the Grounders (not to mention their logo has 12 segments on it, and there are 12 levels, and 12 Grounder clans… did each bunker become a clan? But what about the one they found that failed… Okay, I’m getting off track). I mean, the Second Dawn symbol is in the center of the tattoo. But is it possible that some of the more important members of the Second Dawn were put into hypersleep via a cryochamber in the bunker? In “God Complex”, Gaia mentions that the bunker is the “crypt of the first commander” meaning Becca is buried there. And maybe she is buried there, except alive. If so, that would mean we might be seeing Becca return, and be introduced to the leader of the Second Dawn, Bill Cadogan. One last unforeseen twist

Perhaps the most likely theory outcome is a huge unforeseen twist that changes the entire game. I wouldn’t put it past these writers to throw a huge curveball at us, similar to what they did with A.L.I.E. and the purpose of the City of Light. Considering this is “unforeseen” – we may not even be capable of predicting it. We don’t find out until season 5

Jason Rothenberg said fans would not be satisfied had this been the series finale. Perhaps he just meant that it doesn’t wrap up the show in an adequate way, but he could mean the finale leaves us with a huge cliffhanger.There’s rumors floating around the internet that at a con during the beginning of the season Marie Avgeropoulos, aka Octavia, said that she didn’t know what happened with Praimafaya because they haven’t filmed it yet because that will be next season. Now, I don’t have the proof that she actually said this, it’s just been floating around the web. But let’s hope that’s not the case, because it’s hard enough to wait during the hiatus without a huge cliffhanger. But considering the episode is going to be in real time, it doesn’t sound like we are going to see very much after the Death Wave hits. If it hits. Any theories I missed? Feel free to add them below!