Remember the shocker that awaited Ollie when he entered the Arrow-cave in the midseason finale? A new promo seems like it has a pretty clear answer as to how that "surprise" was possible.
Ollie, of course, discovered Laurel Lance awaiting him, which was a bit of a surprise because 1) Laurel Lance was dead, and 2) the Lazarus pits, the only (currently!) known way to resurrect people in the DC/CW universe, had been destroyed. As this sneak peek shows, it appears Laurel has no idea of what happened to her:
However, this promo for the mid-season premiere, airing in the US January 25, pretty much solves the mystery:
This is an evil Laurel, which presumably means she's the Earth-2 Laurel Lance, a supervillain who goes by the name Black Siren and who made an appearance on The Flash earlier this year. Now, how Earth-2 Laurel made it to Earth-1 is still unknown, but seeing as there are a variety of evil speedsters with the power to run to alternate realities running around (no pun intended) the DC/CW universe, I have to imagine one of them picked her up and dropped her off. But if so, why?
What I really want to mention here is poor Quentin Lance. The man: 1) Thought his eldest daughter Sara died for several years, 2) later discovered she was alive but was an assassin, 3) saw her turn into a superhero that risked her life every night, 4) learned she died for real, thanks to a brainwashed Thea, but 5) then discovered she'd been resurrected by her assassin cult, 6) found out his other daughter Laurel was following in her sister's superheroic footsteps, only 7) for Laurel to get murdered by a magic arsehole, without hope of resurrection. And now he's going to have to deal with the fact that his daughter is back, except it's not really his daughter but also she's evil.
No one in the DC/CW universe has dealt with more crap than Quentin Lance, who, as an alcoholic, seems to have only slipped off the wagon once in all this time. I hope this isn't the insane straw that broke the alcoholic camel's back.