Abbie's so-called "death" has been a pretty big cliffhanger, and I've discussed speculation on the episode discussion blog I made. This is just some similar speculation I've compiled. If you disagree, feel free to leave a comment.
- Abbie is likely not to have died. However, it is possible the tree could've given her supernatural powers, similar to what happened with Jenny and the Shard.
- It will be interesting to see how Daniel reacts to Abbie's "death". I assume the most likely outcome is not going to end well...
Pandora and the Hidden One
- I believe that it could be both ways: Pandora and the Hidden One can still be on the loose, or they may have died when Abbie sacrificed herself. We'll have to see.
Pandora and the Horsemen
- There might be a chance the Pandora could be the Horseman of Conquest. Considering the first Season revolved around Death, the second Season (mostly) revolved around War, and that Conquest is the third horseman, it may be that Pandora could be Conquest and serving the deceased Moloch.