The Climb

"The Climb" is the ninth episode, the mid-season finale of the third season of Arrow and the fifty-fifth episode overall. It aired on December 10, 2014.

Synopsis
Nyssa 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 The League of Assassins will start killing the citizens of Starling City. Laurel is stunned when her father delivers a very special Christmas gift – her mother, Dinah. Meanwhile, Ray tries to make amends with Felicity and Oliver sets a "meeting" with Ra’s al Ghul.

Production
Preparation began September 30 and wrapped up on October 8. Filming began October 9 and ran until October 21.

Continuity

 * While speaking with Caitlin Snow over the phone, Felicity looks at a news article on a yellow streak terrorizing Central City. This references the Reverse Flash's assault in The Flash episode, "The Man in the Yellow Suit".

Trivia

 * The confrontation with Thea is similar to that with Moira. In both cases it involves Malcolm Merlyn, as well as Oliver breaking through a window. And in both cases he gets surprised by them fighting back, and how well they do so.