With just a few hours remaining until Arrow's midseason finale "The Climb" airs on The CW, the network has released a brief featurette and two new clips from this highly-anticipated episode. Executive producer Marc Guggenheim reveals that the final Arrow episode of 2014 is the show's most epic midseason finale, while teasing that this episode also features one of the biggest surprise endings in series history. This featurette also gives us new footage of Matt Nable as Ra's al Ghul, who squares off with Oliver Queen (Stephen Amell) in a showdown fans have been waiting all year for.

Nyssa (guest star Katrina Law) returns to Starling City and tells Oliver that her father, Ra's al Ghul has given Oliver 48 hours to find Sara's killer or the League of Assassins will start killing the citizens of Starling City. Laurel (Katie Cassidy) is stunned when her father (Paul Blackthorne) delivers a very special Christmas gift - her mother, Dinah (guest star Alex Kingston). Meanwhile, Ray (Brandon Routh) tries to make amends with Felicity (Emily Bett Rickards) and Oliver sets a meeting with Ra's al Ghul.

In case you need more Arrow action, we have two new clips that feature guest stars Katrina Law as Nyssa and Alex Kingston as Dinah. The first scene shows Nyssa issues an ultimatum to Oliver, where he must find out who killed Sara Lance (Caity Lotz) within 48 hours, or the people of Starling City will suffer. The second clip shows how surprised Laurel is to see her mother, while lying about the true whereabouts of Sara. Check out the featurette and clips below, before tuning in to "The Climb" later tonight.

RELATED: Arrow Season 4 Finale Trailer Reveals Darhk's Diabolical Plan