>>117227267Grace gets her number down to 0 in the middle of a battle with Simon over the future of the Apex and Amelia. She initially tries to play it off, but Simon kicks her into the way out, and she's sent tumbling through the gate. Her number is gone, and since there's no plan for her to go home, she just stays with One-One and learns more about the train. Amelia takes Hazel away, but not before Simon half apologizes for what happened to Tuba, 'since y'know, it was sort of pointless in the end'.
It's this information that Simon takes back to the Apex Car, and proclaims a new chapter in Apex existence; he that they will not just take the car itself, but seize the train's controls altogether. The Conductor is Dead, Long Live the Conductors. Simon then retires to his diorama, now with the light of the busted spotlight shining on his little fantasy world of simple heroes and villains.
https://www.youtube.com/watch?v=cjURwhAdM1UMeanwhile, Grace wakes up where the door took her, to the one place she wanted to be; The Train. Specifically the very front of it, with One-One. With her number gone, and no emotional baggage, Grace is essentially where she'll be forever; a Denizen of the Train if you will. She realizes what that will mean if Simon and the others find her, but now One-One knows about the Apex too. The season ends with One-One and Grace speaking together, Amelia and Hazel hurrying along multiple cars, and Simon sitting in a throne with a cold expression on his face, the New Apex awaiting their new quest. And they all look, anxiously, at their number hands. Higher than ever. Meaningless. And Gone.
Post-credits Cartoon Network hand scene just shows a corner of the outside of one of the car platforms for a second, before Tuba's battered gorilla arm whips out from under the side, and grips the top, in the same position of all the hands from other episodes this season and we hear a bestial roar. 
