In the last episode of "Arrow" on Dec. 4, Oliver was left for dead, Roy got shot, and we learned that Moira may possibly be in bed with the League of Assassins. But, if you think that was a lot to digest, then start preparing for the Dec. 11 mid-season finale where things will get even worst.

Inspired by the classic movie "A Christmas Carol," Oliver will face multiple hauntings and messages in the holiday-themed episode of "Arrow" entitled "Three Ghosts."

A preview of "Three Ghosts" shows Oliver reaching out to Shado while he is on the examination table. In another clip, he hears Slade Wilson whisper "You are not a hero!" Oddly, Oliver also destroys his own lair and Officer Lance ends up in a hospital bed. The promo also includes a peak at Oliver's new mask.

On top of that, an official synopsis of the upcoming episode released by The CW reveals that someone will die, reports Hollywood Life.

"After a fight with Cyrus Gold AKA the Acolyte (guest star Graham Shiels), Oliver is drugged and left for dead. Determined to cure him, Felicity (Emily Bett Rickards) makes a risky decision. The cure causes Oliver to hallucinate, and what he sees forces him to confront his past. Meanwhile, Barry continues to help Felicity, and their connection grows stronger. The Arrow asks Lance (Paul Blackthorne) to look into Gold, but when the stakeout on Gold goes bad, someone is killed. Roy is captured and tortured by Brother Blood (guest star Kevin Alejandro)."

TV Line also dropped a hint about what to expect in the action-packed midseason finale event. According to the show's executive producer, Andrew Kreisberg, Barry Allen learns that meeting your heroes is not always what it's cracked up to be.

"[Barry is] getting to see that sometimes it's better not meeting your heroes, because they're complicated and cranky... and maybe jealous of the way you're looking at their assistant," said Kreisberg, adding that, "At the end of the day, Oliver just wants the job done and Barry helps get the job done - and that's sort of the saving grace for him."

In addition, TV Line's Ausiello has revealed that new "Arrow" villains will arriving very soon.

"Yes, Clock King's time has come!," says Ausiello. "Sources confirm that the CW hit will introduce the pivotal DC Comics baddie (aka William Tockman) later this season."

S2E9 of "Arrow," "Three Ghosts," airs Wednesday, Dec. 11 at 8 p.m. on The CW.

Watch a preview below.