Kai manages to kidnap Jo by stabbing someone (Jo may suck as a doctor since she apparently though this was caused by a car accident. Presumably a car with a knife) and following them to the hospital because despite the vampires everywhere, hospitals have zero security
Sheriff Liz drops in on Caroline so they can have their special tree-trimming thing in her improbably-huge-dorm-room (even Sheriff Liz snarks this) and she invites Stefan because clearly more relationship drama is necessary. To help move the whole Stefan/Caroline bonding along, Sheriff Liz suddenly feels faint.
Elena and Damon are technically looking for ways to free Bonnie but really Elena is staring at Damon’s uber sexiness. Alaric calls them to come see him – Damon suggests that maybe some precautions may, perhaps, have been useful with the serial killer loose but Alaric scoffs at the very idea. Damon’s plan is to kill Kai. They also add some more exposition – Kai can’t merge with Jo without her magic which is stored in a knife which Damon has hidden – and Kai can’t use a locator spell because he can’t do magic.
Elena joins Caroline at the hospital where they’ve taken Sheriff Liz and they talk about Damon and Elena’s relationship because it’s definitely the thing they should be talking about right now. After compelling a doctor, Elena learns that Sherriff Liz has cancer (vampire blood cure anyone?)
Stefan decides it’s his job to give Caroline the bad news. Apparently vampire blood doesn’t cure cancer – Stefan is sure if it did they’d have heard about it (why? Because there are a huge number of compassionate vampire blood donors out there?) and Liz is incurably ill. Caroline is sure his mother is cancer proof. Ok I’m being unfair this is a really deep, moving scene that if Liz had been given 10 minutes this season – or if they couldn’t just VAMPIRISE her – would be excellently done. And since I’m British and am exposed to British soaps there is absolutely no way shape or form you can get me in the emotions with a tragic Christmas episodes because we are the masters of making people sob piteously over the turkey.
Over to Tyler and his plan is to let Kai live – Luke and Liv aren’t big fans of letting him live since he did try to murder them when they were children, but Tyler thinks letting Kai merge with Jo and becoming a super-powerful serial killer will be an awesome way to spare Luke and Liv from the merging thing. This is why Tyler shouldn’t make plans. Luke points out a super-powerful witch on a killing spree is probably not a good thing, he also has a sense of fated duty towards the coven. But Liv is willing to throw that aside and unleash a serial killer for a normal life.
Unfortunately Liv seems to win the argument because they cast the finding spell for Kai and get him the knife full of Jo’s magic and join him in his evil ritual of sibling bonding (which sounds vaguely incestuous). Kai starts stabbing Jo which shocked Luke that his stabby brother likes stabbing things and nearly gets himself stabbed in the process – so he leaves. Jo points out she has to voluntarily retake her magic back and random stabbing won’t change that (but it could kill her first).
Jo begs Liv to let her go but Liv does point out that Jo trying to avoid the terrible fate of merging means that it falls on Liv and Luke instead, the whole “spare me from this terrible fate so you can have it instead” isn’t a big winner. Except, of course, Kai’s a serial killer. But Liv points out that Jo may win the merging (amusingly, while Liv is willing to consider that, absolutely no-one believes Luke would survive the merge with Liv) and points out how strong she is – which is when Kai comes back and steals Liv’s magic. He tortures Liv until Jo willingly takes back her magic.