If you haven't watched Dark season 3, you need to stay the hell away. This is an explainer of where we stand after the series finale. You can actually click here for an explainer of everything that went on in the first two seasons.
Now, on with the finale...
The finale starts with Claudia approaching Adam, something that hasn't happened in any of the previous loops, which obviously confuses him. She explains that his frequent attempts to destroy the knot have only ever kept it intact, including killing Martha and her unborn child.
Basically, neither Adam’s world and nor Eve’s world should have existed, because they were branches of the timeline created after HG Tannhaus’ experiment went wrong in a third world – the origin world.
Meanwhile, Claudia has spent 33 years across Eve and Adam’s worlds trying to stop the loop from repeating only to realise that it can't be stopped except during the apocalypse when time stands still.
She explains all this to Adam, who then convinces Jonas that the only way he can prevent himself from turning into Adam is to go ahead with the plan of rescuing Martha from Magnus and Franziska and travelling to June 21st 1986, the day on which the passage was opened for the first time.
On this day, HG Tannhaus’ attempt to go back in time to prevent the car crash that kills his family backfires as he accidentally splits time, creating the other worlds, thus starting this insanity.
When the passage is created, there's a portal between all three worlds through which Martha and he travel back to the day of the fatal car crash in the origin world to prevent it from ever happening.
So, are Jonas and Martha dead?
No. Technically, they are just wiped out of existence as Adam and Eve's worlds are never created and they didn't exist in the origin world.
The collapse of the two alternate worlds mean in the origin world, we see a pleasant-looking dinner party with guests including Regina Tidemann (not dead from cancer), Peter Doppler, and a pregnant Hannah, who doesn't have the last name of Mikkel Kahnwald as he doesn't exist anymore...
.. much like Ulrich Nielsen and Charlotte Doppler, who no longer exist, since they needed time travel to be born to begin with.
And the other worlds don't exist anymore, they do seem to have some kind of impact on the characters in the origin world, almost like a deja vu.
Like when Hannah says that she would name her unborn child Jonas after looking at the yellow raincoat that Jonas used to wear.
So why was Adam obsessed with the origin all this time?
Adam was convinced that the 'origin' is the child of Jonas and Earth-2 Martha, which he thought tied the worlds together But in reality, it was his attempted destruction of Martha’s unborn child was just something that fuelled loop further.
The real origin, however, was the car crash which caused HG Tannhaus to create the time machine.
We’re the reason everything happens the way it does. Why it happens again and again... We are responsible for this never-ending Deja Vu.
God damn it! This was some show. Obviously there are still a lot of questions that need answering, but I guess, the creators left it to our imagination So, run wild.