The race for the cure is over, won by a latecomer who surged from behind to steal the prize from everyone else.
The mysterious "other person" wandering around the island turns out to be Katherine! She's back and ends up causing the death of one of the main characters.
But this is "Vampire Diaries" -- is dead ever really dead?
One is the loneliest number
It's morning and Damon is tied to a tree under the watchful gaze of the other hunter, whose name is Vaughn. Seems Vaughn has been watching their crew for quite some time. His agenda is to wake up Silas, then stuff the cure down his throat and kill him.
Elsewhere, with Jeremy and Bonnie missing, Elena and company need help decoding the tattoo. Caroline and Tyler find Klaus's sword, but it's got a cryptex (you know, like in "The Da Vinci Code"). Unfortunately, it's written in Aramaic and could take weeks to translate. Luckily (or unluckily), there is someone there who speaks the dead language fluently -- Klaus!
He helps them solve the cryptex, just as Vaughn reveals the same information to Damon: There's only one dose of the cure! Everyone's plans for a happy, normal, human life … down the toilet!
Klaus shouts the information to Rebekah, who's on the phone. She wants the cure for herself, of course, and gets Stefan to admit that he'd still give it to Elena. So, Rebekah breaks his neck and takes off on her own.
At the magical well/cave, Shane pays off his witch with Silas's tombstone (apparently, it's more valuable than the Hope Diamond), then he, Jeremy, and Bonnie rappel down. While they're alone, Bonnie confesses she has no intention of helping Shane raise Silas. When she performs a spell that sucks Jeremy's tattoo (as well as Vaughn's) off his body, the cave begins to shake, and boulders crash down on them. The three of them are buried under rubble.
Jeremy wakes up and unearths Bonnie, but Shane's leg is broken. Oh well, Bonnie snarks … better stay off of it. They head into the opening that the cave-in revealed on their way to Silas's grave.
Damon and Vaughn arrive hot on their heels, but Vaughn doesn't need Damon anymore and prepares to kill him. They duke it out, when Rebekah shows up (to save the day?).
Back on ground level, Stefan wakes up with Elena beside him. They talk about how there's only the single dose of the cure, and Elena says she wouldn't take it over everyone else. And maybe it's a blessing in disguise. "Even if I could be human again, I wouldn't be the person that I was," she notes. But there's no time for a pity party -- Klaus won't be trapped in his invisible box for long. They reenter the race.
Rebekah thinks she can squash Vaughn like a bug, but this hunter has some nifty toys. He neutralizes her with a kind of wooden-bullet bomb, then is about to kill Damon when Stefan and Elena rush in to save him. Vaughn and Elena both disappear toward the tomb, but Elena is attacked by a mysterious stranger.
Stefan patches up Damon, who urges his brother to go get the cure for Elena. Later, after Damon picks out the wooden bullets from Rebekah's back, she calls him selfless and very nearly a good person (which we've always known).
Meanwhile, Jeremy and Bonnie are drawing close when she sees her grams! She's elated, until Jeremy realizes he can't see grams. And since he can see ghosts, that means thisgGrams is just a hallucination brought on by Silas. (Also, Shane's wife must've been a hallucination, too.)
Back in Mystic Falls, Caroline and Tyler realize that if they can't get the cure to give to Klaus, the original will come after Tyler. She begs Klaus to reprieve her boyfriend, but how would that look to all the other vampires? He notes that Caroline wouldn't take the cure herself because she likes being a vampire. She then challenges him to show her how alike they are by letting Tyler run away. "Show him the mercy I would show you," she pleads.