The CW is all about giving its viewers heartthrobs and heart attacks if the mid-season finales of The Flash and Arrow are any indication.  While the former ended with at least a brief flare of hope for a better tomorrow, the latter ended on a literal cliffhanger.  And I don't know if I've seen a braver (or bolder) conclusion to an episode than this one tonight.  Fans of DC mythology are probably equal parts excited about/confident in what's coming up on the second half of this season, but for those of you who aren't in the know, just trust me when I say that everything's going to turn out (mostly) fine.

Hit the jump for our Arrow recap.

Much like last night's mid-season finale of The Flash, tonight's Arrow opens with a verbatim translation of the episode's title, ie Oliver climbing a snowy mountain cliff.  We continue to cut back to this climb throughout the episode, but for the sake of consistency, we'll save this part of the recap until a bit later when it reaches its climax.  Instead, 48 hours earlier, Arrow delivers a wanted criminal to Quentin Lance in the back alley outside of the police department's holiday party.  While Lance heads back inside to celebrate, Arrow gets attacked by the Dark Archer (who he assumes to be Malcolm Merlyn) and a squad of fellow archers.  In fact, Nyssa al Ghul is behind the attack, which succeeds in knocking Queen out and kidnapping him.  Nyssa gives Queen 48 hours to find Sara's killer before she'll unleash the League of Assassins on Starling City.  One of those assassins is Queen's former ally, Maseo Yamashiro.

Laurel is at Sara's grave wishing her a "Merry Christmas", and Thea drops by.  Sometimes it's easy to forget what Thea does and doesn't know since she's been in and out of this season, so Laurel breaks the news that Sara was murdered.  I smell a red herring, but maybe that's just the lingering effects of last night's events on The Flash.

Meanwhile, Oliver breaks the news to his team that they have only 48 hours before all hell breaks loose.  Felicity receives the DNA evidence from Caitlin at S.T.A.R. Labs and crosschecks it against a database of known criminals in the last few years.  One name matches: Oliver Queen.  (Or perhaps someone who either has access to his DNA to set him up, or shares DNA in common with him...)

The team tracks Malcolm Merlyn's movements around the world to see if he had anything to do with Sara's death.  The intel leads Arrow and Arsenal to beat up on a pilot, who gives them security footage from Merlyn's arrival in Starling City the night before Sara's death ... accompanied by Thea herself!  Oliver quickly realizes that not only did Thea lie to him, but that she's in league with his archenemy.  Not good news for anyone.  Thankfully, Diggle brings up the theory that another Queen could have killed Sara, and Felicity and Roy support the idea, even if Oliver doesn't.  He's convinced Merlyn set him up, and plans to find out from Thea herself.  Back at the Queen household, Oliver asks Thea about her relationship with Malcolm, and catches her in a lie.  Felicity knows that Oliver can't interrogate Thea, so she suggests that he questions her as the Arrow.  That results in a rather unexpected (but brief) fight between the two that ends with Thea jumping over the ledge of her highrise loft in defense of her father.  Okay then!

In between all of this, Ray Palmer complicates things by showing up at Verdant while the team is going through a tough trial in the sub-basement.  Palmer apologizes to Felicity and explains why he's a bit reluctant when it comes to relationships.  Apparently Slade's men broke his leg in a fight during the riots in the city, then broke his girlfriend's neck while he watched, helpless.  (That's one way to work your way back into Felicity's heart, I guess, even though he's still a super-stalker...)

Back at the club, Malcolm arrives to confront Oliver, who's close to going back on his word to never kill again.  With his appearance comes a video revealing Thea's role in the assassination of Sara, though it was under the influence of drugs (and Malcolm Merlyn).  Merlyn's plan was to give Oliver a chance to claim the role of Sara's killer, challenge Ra's to trial by combat, and by defeating him, clear his blood debts (both Merlyn's and Thea's).  That Malcolm is a straight-up jerk, so I'm not sure why Oliver didn't just kill him right there, contingency plans be damned.  Now, Oliver has a clear path ahead of him even if he doesn't like it: duel Ra's to protect Thea.  (This whole plot twist fell a little flat, but I think that's due mostly to the rush job of setting up the punchline in this last episode.)  Before he leaves, Oliver tries to explain to Thea one last time that Malcolm doesn't love her, and that he isn't capable of such emotion.  He essentially says goodbye to her as the camera closes out on a shot of the siblings' snowman ornaments hanging next to each other on the tree.

In a continuing mess of an editing job in this hour, Palmer and Felicity have another spat.  She wants to know why he bought Queen Consolidated, so he intends to show her.  He reveals his plan to condense the company's military technology into O.M.A.C., which he renames A.T.O.M., advanced technology operating mechanism.  He wants to use the suit to help protect the city, and he wants her help in doing so.

As Oliver says goodbye to Roy and Diggle, Felicity shows up to have (perhaps) a final heart-to-heart with him.  Surprisingly, she wants him to kill Ra's al Ghul, since it's a duel to the death and she's worried that he's not a killer.  Before he departs, he confesses to loving Felicity once more.  Eh, I feel like we've gone down this road one too many times already, but it is The CW.  What say you?

In a less superheroic side story, Alex Kingston arrives as Dinah Lance in a Christmas surprise for Laurel; too bad her arrival is overshadowed by Sara's death, news which is kept from her mother.  The ladies chat over a cup of coffee and Dinah sniffs out the trouble with Sara rather quickly.  If you were wondering whether or not Sara would make a miraculous comeback, Dinah's intuition seems to put that to rest.  Laurel confesses that Sara died, but that Quentin doesn't know, so they have to keep it a secret.  Laurel also tells her mother that she's going to find Sara's killer and make them pay; Dinah is totally on board with this.

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In our usual flashback sequence, Oliver arrives in his Hong Kong home after a bloody interrogation.  Maseo offers him food and advice on how to get past his queasiness.  Oliver reveals the intel he discovered, that of a supervirus developed by a company looking for a novel antibiotic; this new bioweapon has been dubbed "Omega". Oliver and Maseo infiltrate BTHK Biotech to take Omega; the only problem is that an inside man already retrieved the virus for China White.  They track him down rather easily and threaten to torture him to find out what he knows.

Unfortunately this interrogation isn't working, so Maseo suggests using an influential drug to get intel.  They'll have to hurry up since China White kicks in the door of the Yamashiro residence in order to threaten Tatsu and her son.  Too bad for White that Tatsu, aka Katana, is rather skilled with the blade.  However, it seems China White was too much for Tatsu, as the latter gets herself kidnapped.

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In another mini-flashback, Ra's al Ghul is training, slaughtering his own men with finesse single-handedly.  When Nyssa tells her father that Oliver has yet to return with Sara's killer, the leader of the League plans to make good on his threat.  Just hang on, Ra's, Ollie's on his way!  Finally, Oliver arrives before Ra's.  He claims responsibility for Sara's death, saying that she begged him to do it and sever her ties with the League.  Ra's isn't buying it, but he accepts Oliver's challenge.  In order to even make it to the bloody fight, Oliver has to make it to the sacred site of the League...

Now let's talk about that climb.  The tension of it is played out fairly well since Oliver's progress is glimpsed bit by bit throughout the episode.  It's deadly and treacherous and harrowing, serving to test Oliver's will, strength, and stamina, but also to weaken him before the final fight.  Did it work?

Oliver disrobes and chooses his swords while Ra's tells him of the first time he killed a man, at the age of only 15.  While he lamented taking the man's light from behind his eyes, he was proud at replacing his evil with death.  Ra's claims to have killed thousands, but it doesn't deter Oliver from telling him it's his last fight.  While Oliver uses two swords to attack, Ra's battles him unarmed ... at least until he takes his weapons from him.  Ra's handles Oliver rather easily, dodging, disarming, and striking with grace and precision.  Oliver is outmatched.  Though he shows a glimmer of hope, Ra's crushes his throat, stabs him multiple times, and blesses him before sending him over the edge of the cliff.

Comicbook fans, I know that you know what's coming, but for the sake of those of you who don't, I won't be going into any spoilers here.  Let's just use a bit of logic and say that, of course Ollie will be back "somehow" or the second half of the season will have to be retitled "The Many Loves of Felicity Smoak."  Regardless of how the hooded hero returns, that was a pretty ballsy move by the Arrow writers to, for all intents and purposes, kill their title hero before a winter break.  Kudos, Team Arrow!  I for one will be anxiously awaiting your return in late January!  Let's hope Arsenal, Diggle & Felicity, Wildcat, Black Canary, and A.T.O.M. can keep from failing this city!

Rating: A- (The editing was a mess and there were lots of loose ends left dangling, but that conclusion gave the mid-season finale a big boost.)

Quips & Quivers:

• Nyssa: "Sara is dead. It's time you remember that."
• Quick nod to the events of The Flash mid-season finale in a news headline talking about the Yellow Blur at S.T.A.R. Labs.
• Ra's al Ghul: "You're just a boy.  Mr. Queen, you failed to protect the city you love; now you will watch it bleed." I love Ra's using Arrow's own words against him.

• 

  Ra's al Ghul: "It's been 67 years since someone challenged me. You covet death that much?" Oliver: "Do you accept?" Ra's: "Oh yes." Winks and nudges.
• Laurel: "I swear, I'll find Sara's killer and make them pay."  Dinah: "You make them pay, and you make them suffer."
• Felicity: "Why does this keep happening to me?"
• Oliver: "Felicity, I don't know if I'm a killer anymore, but I do know two things: The first is that, whoever I am, I'm someone who will do whatever it takes - whatever it takes, to save my sister." Felicity: "And the second thing?" Oliver: "I love you."  I'm sure Olicity fans lost it at this point, but it felt a bit forced to me.  Sorry.
• Maseo: "Remove your shirt.  This is custom." Right, custom on The CW. Enjoy!
• Ra's: "You should take pride. You survived longer than most."
• Ra's: "Don't be afraid, my son. Death comes for us all. You can only evade it for so long."
• If Ollie's confession of love for Felicity didn't melt the fans, then that last lingering shot of his life flashing before his eyes certainly did the trick. Heartstrings, you are tugged!

Arrow returns to The CW starting January 21st!