You’ve got to hand it to Katherine; the girl’s a meticulous planner. So when Damon throws a wrench into her Mason Lockwood machinations in tonight’s episode, “Plan B,” we see how easily the evil vampiress can turn the lives of our intrepid heroes upside down with a single phone call. And how!

But Katherine’s not the only one with solid organizational skills; episode scribes Elizabeth Craft and Sarah Fain, veterans of Joss Whedon’s “Angel” and co-show runners of “Dollhouse,” must have kept impeccable notes on the flurry of plot threads and character movements that unfold in the fast-moving “Plan B,” in which just about every character in Mystic Falls gets some action. (Insert clever contraceptive joke here.)

Get ready to pay attention, folks – this episode is full of metaphorical doors opening and closing, juggling storylines, dueling dualities, new mythologies and unsettling revelations, two amusing if random Indiana Jones references, pretty boys in agony, pretty boys in tears, and the official inauguration of Steven R. McQueen into the Derek Zoolander Club for Serious-Face Actors. (Paul Wesley and Ian Somerhalder are already members.)

 [Full recap of Thursday's (Oct. 21) "The Vampire Diaries," titled "Plan B," after the break…]

 

Nina Dobrev is in bed with two men at once! While Elena and Stefan make romantic kissy-face and worry that Katherine will find out they’re not really fighting, Katherine’s tumbling around with Mason Lockwood. Mason tells Katherine he doesn’t trust her, but he loves her. He tells her he’ll give her the moonstone later that night.

And if you think dueling Dobrevs are hard to follow, wait ‘til you get a load of the storylines that pop up in the first five minutes: Jeremy wants in on Damon and Alaric’s sleuthing, Bonnie’s still the Debbie Downer of Mystic Falls, Caroline tries to reconnect with her mom, and everyone’s pitching in to prepare for the annual Mystic Falls Masquerade Ball! Also, Aunt Jenna tells Stefan that she heard him and Elena doing it that morning. Gross.

Alaric, Damon, and Jeremy talk Aztec legends. According to lore found in Isobel’s Duke University research, Mason’s precious moonstone is used to “seal” the werewolf curse. They wonder if Mason hopes to use the stone to reverse it.

Elena fills Bonnie in on how Katherine used Caroline and why she and Stefan are fake fighting, so naturally Bonnie makes it all about herself. She feels left out of her BFF Elena’s life. Elsewhere at the masquerade prep party, Mason is surprised to find Stefan still alive. Er, undead. Still undead? Whatever. Stefan tells him that they’ve got Sheriff Forbes tucked away safe somewhere. As he leaves, Bonnie brushes by Mason and gets a witchy vision of him kissing Katherine. Gross. So far, TMI about other people’s sexy time is a running theme. Let’s see where this goes.

Damon can’t shake off his new sidekick, so he tells the overprotective Elena about Jeremy’s eagerness to join his and Alaric’s CSI: Mystic Falls werewolf investigation team. Elena tells Jeremy that it’s dangerous to hang around Damon, but Jeremy tells her that she’s not the boss of him!

Stefan and Damon get on the same page about Mason’s involvement with Katherine and determine that Katherine must be using him to get to the moonstone. Duh, people. Meanwhile, Tyler and Matt get on the same page about Caroline, and Tyler advises Matt that sometimes you have to take the good with the bad.

Jeremy dives into this werewolf snooping business with youthful enthusiasm, prompting Damon to refer to him as Indiana Jones. We see him more as a Sean Patrick Flanery in “The Young Indiana Jones Chronicles” kind of Indy ourselves. Steven R. McQueen pulls off his first feat: acting like someone who can’t act as Jeremy awkwardly probes Tyler about the moonstone. The brothers Salvatore overhear Tyler say he gave the moonstone to Mason, and recruit Bonnie into their mystery team in an effort to steal the stone.

Elena is forced to sit out the fun in order to maintain the pretense of her fake fight with Stefan, and being out of the loop for the first time ever is KILLING HER. She turns into the annoying girlfriend who has to call her boyfriend if he doesn’t text her back right away. Stupid Elena. As Elena obsesses in agony waiting for her phone to ring, Bonnie mindheads Mason with her witchy migraine powers and helps Stefan and Damon kidnap him.

Over in the Salvatore dungeon, Caroline’s been explaining vampire life to her mom and insists that she’s making lemonade out of the lemons that vampire life has given her. Upstairs, Bonnie grudgingly helps Stefan tie up the unconscious Mason in the Salvatore study. She uses another witchy power to read Mason’s mind, searching for information on the moonstone’s whereabouts. She tells Damon the stone is in a well somewhere, then splits as Mason wakes up. On her way out, Bonnie tells Caroline she’s heading to the old well on the edge of the Lockwood property to look for the stone, and after hesitating accepts Caroline’s company.

Back at the masquerade pre-party, poor Matt asks Elena if Caroline’s seeing someone else because she’s been totally MIA lately. Stefan gets a text from Bonnie about the moonstone and the old well but avoids Elena to maintain their faux-fight, which drives her nuts. (Executives somewhere are high fiving themselves for all the product placement in this episode, in which cell phones are so desirable that the teenagers of Mystic Falls use their mobiles to Google things and then go crazy over text messages! And just wait ‘til you see terrible things that LAND LINES will bring into your lives later on…)

Elena is visibly upset by being left out of all the fun and impulsively follows Stefan out to the well. Stefan jumps in to search for the moonstone, but finds himself waist deep… in vervain water! Duh duh duhhhhh! Back at home, Damon tests and tortures Mason with a hot poker, digging for information. Jeremy walks in with a box of Isobel’s research that Alaric brought home; he found a mysterious dried plant called wolfsbane – why, it’s vervain for werewolves! Damon gently caresses Mason’s pretty face with the stuff as he interrogates him about Katherine. Jeremy watches uncomfortably as Mason writhes in pain.

Back at the well Caroline and Bonnie find Elena and help rappel her down to Stefan. Elena finds her boyfriend face down in the vervain water, his pretty face all burned and melty. Gross. Elena finds a locked box submerged in the well – score! – and then totally freaks out for a second when snakes attack. Snakes. Why’d it have to be snakes? Elena gives the injured Stefan her own blood to drink to heal.

Meanwhile, Jeremy’s fragile human constitution has had enough of watching Mason vomit up his insides, but Damon’s making progress with the wolfsbane. Mason tells Damon the moonstone’s in the well, and that he’s getting it for Katherine so that she can reverse his werewolf curse … because she loves him. Damon scoffs and tells Mason that Katherine’s just using him. He prepares to kill Mason and orders Jeremy out, but Jeremy stays and pleads for leniency, which leads Damon to utter the title of the previous episode: “Kill or be killed,” he snarls. “Suck it up or leave.” Mason, now utterly sympathetic, asks Jeremy to watch out for Tyler and make sure he doesn’t succumb to the family curse.

Jeremy leaves as Damon gets those crazy eyes -- the same ones we saw the last time Katherine drove him mad with jealousy and he snapped Jeremy’s neck. He lectures Mason, saying that he understands that Mason loves Katherine because he used to be that guy; Mason seems to want Damon to end his cursed life. Damon reaches into Mason’s chest and literally rips out his heart.

Alaric and Jenna have their first romantic dinner date. He cooks! She swoons. We snooze.

Back in the Salvatore dungeon, Caroline tells her mom about her day. She’s thrilled that while they rescued Stefan, Bonnie was totally nice to her. Just like old times! Mama Forbes is shocked that becoming a vampire has transformed Caroline into the strong and confident young lady she never was in life, and realizes that she still loves her little girl. She asks that Caroline not compel her to forget everything after all and promises to keep her secret.

With tears in her eyes, Caroline tells her mom she trusts her… but knows that her mom will never trust her vampire friends. Caroline compels Mama Forbes after all, making her forget the best mother-daughter day they ever shared. She resets her mother’s memory back to how it was before – cold and distant. Between this and breaking up with Matt for his own good, Caroline Forbes has emerged the most conscientious vampire on this show. How did we ever doubt her awesomeness?

Stefan returns home to find Damon wrapping up Mason Lockwood’s body and they begin to dispose of his personal items. But Damon’s still feeling demented, and over Stefan’s objections he calls Katherine on Mason’s phone to taunt her. Damon reveals that he killed Mason and has the moonstone, reveling in his victory over Katherine, but she taunts right back: With Mason dead, she’s kicking her Plan B into action.

And that plan is… calling Elena at home. Aunt Jenna answers the phone and hands it to Elena. Katherine tells Elena that she knows her fight with Stefan wasn’t real. What’s more, she knows about their romantic interlude that morning. (But wait, we thought no one but clueless Aunt Jenna knew about that! Ah, the value of TMI.) “I will always know,” she tells Elena. “I will always be one step ahead of you.” 

Because this scene is unfolding so deliciously and because we suddenly remember that Jenna oddly said “Of course, I understand” before giving the phone to Elena, this scene becomes more exciting than hunky werewolves fighting with hunky vampires and BFFs working together and mommy love.  And as Katherine reveals to Elena that she’s been slipping secretly into the house weaning Aunt Jenna off of vervain so she can control her, we become very aware that Jenna’s in the background chopping vegetables with a very large knife while Alaric stands, confused and in the dark, a few feet away.

As Katherine taunts Elena over the LAND LINE telephone, Jenna plunges the knife into her own stomach and collapses on the kitchen floor. See, kids? Stick with cellular technology and these things won’t happen!

Luckily for Jenna, she’s about as good at following orders as she is at parenting; she missed her vital organs and will recover just fine. Still, Elena’s shaken up as she fills Jeremy in at the hospital, explaining that Katherine did it to send a message to their whole Brat Pack that she can get to anybody. Steven R. McQueen then pulls out his second Acting Coup of the episode with a soap opera-worthy smolder as Jeremy promises the distraught Elena that Katherine will pay for what she’s done. Oh, yes. SHE WILL PAY!

The recurring theme of duality continues as Tyler comes home to find he’s lost his uncle, though he doesn’t quite know yet how dead Mason is. Mayoress Lockwood breaks the news to Tyler: Mason has apparently packed up and returned to Florida, the state to which everyone retires sooner or later.

After the day’s traumatic events, a teary-eyed Elena tells a teary-eyed Stefan that they should have listened to Katherine in the first place, because by being together they’ve put their loved ones in danger. Elena reluctantly breaks up with Stefan. So great is their pain that even Damon feels bad; he apologizes for provoking Katherine by killing Mason, but Elena has given up. Katherine has won.

But wait, there’s more! Since we can’t leave this episode off-balance, Katherine recruits a new pawn for her Plan B. With Mason gone she needs a new werewolf, so she orders a mind-controlled Matt to attack Tyler … until Tyler kills him.

Next week: The brothers Salvatore conspire to kill Katherine at the Mystic Falls Masquerade Ball!