The CW's Legends of Tomorrow broke fans' hearts during the "Crisis on Earth-X" crossover this year with the death of Professor Martin Stein, one half of Firestorm. That heartbreak was only made more difficult when, the very next week, the team encountered their friend's younger self as a time anachronism during the show's midseason finale.
While we know that Stein's death is a result of Victor Garber wanting to move on from the time-traveling DC Comics-based series, that hasn't stopped fans from wondering just how final death is in the Arrowverse, and specifically on Legends of Tomorrow. The team encountering a very much alive young Stein (Graeme McComb) while the proverbial dirt was still fresh on Stein's grave seems a little too convenient, and even though Jax's (Franz Drameh) effort to prevent the tragic death by taking advantage of a loophole seemed to have failed, we have to wonder if Stein really and truly is dead and gone.
The biggest thing that leads us to believe that Stein might not be dead forever is that loophole Jax tried to take advantage of. In the episode, Jax gives Stein a letter that would give the older Stein the information he needed to prevent his death at the hands of Earth-X Nazis. Because young Stein was instructed to not read the note until a very specific date, Jax avoids messing up time any more than it already has been, but could still save Stein. However, Stein destroys the letter without reading it. This leads Jax to confront him, with young Stein saying that he accepts whatever his fate is -- words that echo his older self right before he died.
But here's the problem with that and the idea that it somehow still works within the idea of the loophole. Jax gave young Stein a specific date when he could read that note, and young Stein knew that the note dealt with his death. Stein's a brilliant scientist, and presumably pretty good at math, so he can put two and two together to figure out that that date is the date he is set to die. Just because young Stein chose not to read the note and therefore doesn't know exactly how he dies, he now has a pretty big piece of information that he shouldn't have.
Even though Gideon didn't detect any change in the timeline at this point, that doesn't mean the opportunity isn't there for an older Stein, aware of the date of his death, to do something different that would result in him surviving the Earth-X Nazis, or potentially avoiding that mission altogether and just going home to his family. If there's one thing we've seen on Legends it's that time isn't linear. Anything can happen.
And that Jax was even able to interact with young Stein while his grief was still fresh enough that he'd want to save his future father figure is another clue that maybe Stein still could survive. Weird coincidences have been happening when it comes to the Legends dealing with anachronisms. The team keeps running into either their younger selves or people close to them in different places within the timeline. It's getting weird enough that even members of the team -- specifically Zari (Tala Ashe) -- have noticed that something seems deliberate about the anachronisms they're chasing. This has caused us to speculate that the timeline might be imploding around the Legends, and while that has bigger implications for the Arrowverse at large, an implosion could serve as a sort of reset, possibly returning Stein to the living timeline, still off the team (and show) because he's retired to be with his family as planned.
As for why the timeline would be imploding? Well, the Legends didn't help things last season when they interacted with themselves to stop the Legion of Doom, but considering that Eobard Thawne seems to be able to cheat death somehow, we're just going to blame The Flash.
Legends of Tomorrow is currently on winter hiatus and will return in February.