The CW has released a featurette going behind the scenes of "The Climb," tonight's Arrow midseason finale that executive producer Marc Guggenheim told us is a "game changer" that will leave viewers asking "Did they really just do that?"
In the video, Guggenheim tells an official CW camera crew that the episode has possibly the biggest twist ending they've ever done in Arrow.
You can check it out below, along with the official synopsis for the episode.
“The Climb” — (8:00-9:00 p.m. ET) (TV-14, V) (HDTV)
RA’S AL GHUL GIVES OLIVER AN ULTIMATUM; DINAH LANCE PAYS LAUREL A VISIT— Nyssa (guest star Katrina Law) returns to Starling City and tells Oliver (Stephen Amell) that her father, Ra’s al Ghul (guest star Matt Nable) 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. Thor Freudenthal directed the episode written by Jake Coburn & Keto Shimizu (#309). Original airdate 12/10/2014.