I only just got fully caught up with 12 Monkeys, and I have a saddening theory. Remember back when Cassie had to travel back and meet with Jennifer? Then you'll also remember that the sheet stated that the latter would die in 2044. Unfortunately, the future is in 2044 this season, meaning future Jennifer will die. This will happen in the next episode. In the preview, despite it being full of action, one part stood out the most. It was future Jennifer repeating that there were many endings, but instead replacing the last part of the phrase with "and this is one of them." The way I processed it, I was able to deduce that that will be the episode where, unfortunately, she dies. I would give anything for wise, old, future Jennifer to live longer, but at least we will still have present Jennifer.