"Arrow" returns for its fifth season in January and with that comes Laurel Lance's (Katie Cassidy) comeback. In the newly released trailer for episode 10 titled, "Who Are You?" the circumstances behind Laurel's return was finally revealed, and it doesn't bode well for Oliver Queen's (Stephen Amell) vigilante team.

Laurel seemingly returned from the dead during the closing moments of "Arrow" Season 5's fall finale, appearing in Team Arrow's lair much to the shock of everyone, according to Screen Rant. In the newly released promo, which you can watch below, Oliver was seen welcoming Laurel home.

Another scene showed Laurel using a sonic scream right before Oliver saying, "That's not our Laurel." She replies with, "Finally, it's about time someone figured it out."

Team Arrow's Laurel was able to manage her sonic scream ability thanks to Cisco Ramon's (Carlos Valdes) technology. The latest "Arrow" Season 5 trailer indicated that the Laurel everyone welcomed back is actually her Earth-2 version, who was introduced on "The Flash" Season 2 as the supervillain Black Siren.

The Earth-2 version of Laurel was both a metahuman and a lieutenant in Zoom's (Jay Garrick) army. The last time viewers saw Black Siren, she was trapped in the S.T.A.R. Labs particle accelerator pipeline with other no-good metahumans.

Judging from the latest "Arrow trailer," the antagonist escaped that predicament and managed to infiltrate Star City, specifically Laurel's family and friends. It's highly possible that Black Siren's arrival hides a bigger motive than what was obvious.

The "Who Are You?" trailer of "Arrow" Season 5 also showed D.A. Adrian Chase (Josh Segarra) figuring out the real circumstances behind Billy Malone's (Tyler Ritter) death in the fall finale. Adrian confronts Oliver about his discovery, while Dig (David Ramsey) prepares to deal with the charges against him.

In "Arrow's" fall finale, Oliver unintentionally killed Billy, his ex-fiancee Felicity's (Emily Bett Rickards) new boyfriend. Oliver was led to believe that he was chasing the latest big baddie Prometheus. He fired arrows into the costumed man's body, only to discover after removing his mark that he was Billy.

"Arrow" showrunner Wendy Mericle said that Felicity won't blame Oliver for this tragedy, but admitted that she was definitely heartbroken for herself, Oliver, and Malone, TVLine reported. The event will push Felicity towards a "darker place" and avenge her dead beau by going after Prometheus herself. In the process, Felicity will do "pretty morally questionable" things.

"Who Are You?" airs on Wednesday, Jan. 25 at 8 PM on The CW.