Damien Darhk (Neal McDonough) is prepared to launch a breathtaking attack on Oliver Queen (Stephen Amell) in the midseason finale of "Arrow" season 4.

Based on the trailer for the episode titled "Dark Waters," the supposedly festive mayoralty party hosted by Oliver turns into a big disaster when Damien and his followers from H.I.V.E. decide to gatecrash.

It looks like Darhk knows how to hurt Oliver when his organization abducted the Arrow's lady love Felicity Smoak (Emily Bett Rickards) right in front of him. According to the evil H.I.V.E. leader, the best way to hurt someone is to take away the person they love the most. "As long as they're alive, you have something to fight for, that is what I am taking away from you," Darhk says in the promo video.

But will Felicity meet her untimely end in the midseason finale of "Arrow" season 4?

In the trailer, Oliver and Felicity are separated by a thick glass. While the two struggle to break the barrier between them, Felicity seems to be losing her breath. Can Green Arrow save her before it is too late?

Fans of the series can remember that someone was in a grave in the premiere episode of "Arrow" season 4. But up to now, the identity of the person is still undisclosed.

However, series co-showrunner Wendy Mericle revealed in a spoiler on TVLine that the identity of the person in the grave will be revealed soon.

According to Mericle, there could be more flash-forwards seen right around the midseason finale of the series. It could add to the mystery of the person in the grave. "We're definitely toying with that," the executive producer added, "and when and if we do decide to do that, it will reveal even more pertinent information about not who's going to be in the grave but certainly where our characters are when that [death] happens."

"Arrow" season 4 midseason finale airs Wednesday, Dec. 9, on The CW.