Arrow's midseason finale ended with a major cliffhanger: Oliver Queen (Stephen Amell) walking into the Team Arrow lair, only to be greeted by Laurel Lance (Katie Cassidy).

For most people, unexpectedly running into your ex who recently declared her unrequited love for you would be a tad awkward, but the strangeness of this situation went far beyond that, given the fact that Laurel was brutally murdered by Damien Darhk (Neal McDonough) last season. So how is Laurel up and walking around again? We break down everything you need to know about her mysterious return.

It's not the same Laurel who died: As the trailer made clear, this is not the late, great Earth-1 Dinah Laurel Lance — although she does appear to masquerade as Earth-1 Laurel for at least part of the midseason premiere. So who is this Laurel? The most obvious answer is Earth-2 Laurel, aka the villain Black Siren.

In The Flash's second season, Team Flash took a trip to Earth-2, where they came across Laurel's doppelganger, a metahuman and high-ranking lieutenant in Zoom's army. But before Black Siren could do too much damage, she was defeated and imprisoned in STAR Labs.

If this new Laurel is, in fact, Black Siren, it would set up a really great nod to the comic book version of Laurel. In the comics, Laurel was an Earth-2 metahuman who moved to Earth-1, which is where she met the Green Arrow. Sound familiar?

She's probably up to no good: As to how Black Siren potentially escaped STAR Labs, all signs point to Prometheus. Since Prometheus' goal isn't to kill Oliver, but to torture him, there really would be no better way to mess with Oli's mind than to make him think Laurel had come back from the dead. And since Evelyn has already been outed as Prometheus' mole, Prometheus could use some eyes on the inside of Team Arrow's operation.

She's going to stick around for a while: After Earth-1 Laurel was killed off last year, Cassidy signed a new contract that made her a series regular across all the Arrowverse shows. That means she'll be making appearances not just on Arrow, but also on The Flash, Supergirl and Legends of Tomorrow. But she'll hopefully be sticking around on Arrow for a while before jetting off to the other shows.

This season of Arrow is all about Oliver struggling to move forward, as his new motto — "the shark that does not swim, drowns" — makes abundantly clear. And the biggest thing holding Oliver back right now is his feelings over Laurel's death. It's why he started killing again. It's why he began going on missions alone. And ultimately, it's why he accidentally killed Det. Malone (Tyler Ritter).

Therefore, it's likely that this season will end with Oliver learning to let go of his grief over Earth-1 Laurel and embrace moving forward — an epiphany Earth-2 Laurel could come to represent. But that's only scratching the surface of all the interesting ways Earth-2 Laurel and Oliver's relationship could go. It would really be a shame if she left too soon to give this new dynamic its due.

She might become the next Black Canary: Other than Oliver Queen, the Black Canary is the most important figure in the Green Arrow canon. That's why it's inconceivable that we'll never see another Black Canary in this world again. However, it's also inconceivable that we see anyone other than Laurel Lance take on the Black Canary mantle.

The show has given us other Canaries, including Sara (Caity Lotz) as Canary/White Canary and Evelyn's brief impersonation of the Black Canary. But the Black Canary isn't just a title that anyone can pick up. It's intrinsically tied to Laurel Lance, the same way Green Arrow is tied to Oliver Queen (which is might be why Connor Hawke never really took off).

That's why it's highly likely that this season might see the redemption of the Black Siren, leading to her eventually becoming the Black Canary — a new, edgier and metahuman version of the one we saw before. This could also prove to be an opportunity for the show to redeem itself regarding its treatment of Earth-1 Laurel, who was often sidelined and never allowed to live up to her full potential.

Arrow returns Wednesday at 8/7c on The CW.

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