‘Vampire Diaries’ Season 5 Spoilers: Episode 15 Synopsis Leaked Online; What Will Happen In ‘Gone Girl’? [PHOTOS & VIDEO]

Get ready for an intense episode of “The Vampire Diaries.” Episode 15 of the CW series is set to be an all-out war as the Mystic Falls gang tries their best to get Elena back … without letting Katherine know that they are on to her. Will the gang be able to succeed? Or does the title, “Gone Girl,” hint that Elena’s never coming back?

When we left off in episode 14, Katherine (as Elena) had managed to seduce Stefan while on a road trip to rescue Damon. Besides acting a little more flirtatious with the younger Salvatore brother, Katherine had everyone fooled into thinking she was Elena's innocent doppelganger – that is until she made the mistake of kicking a stake toward Stefan for him to kill Damon. And while Damon might be overcome with hunger to feed on other vampires, he was still able to pick up on the fact that his ex-girlfriend was definitely not acting like herself. But the real kicker came at the end of the episode when Tyler bit Nadia … poisoning her with his werewolf venom.

Where does that leave “Vampire Diaries” fans in episode 15? In a race to save Elena before Katherine discovers that her secret is out.

According to a leaked synopsis for “Gone Girl,” Nadia’s werewolf bite will lead her to take a trip down memory lane as she “remembers her centuries-long search for her mother.” The blast from the past could potentially lead to a flashback of Nadia as a child in the 1400s – something that fans saw a peek of behind the scenes in late December.

As Nadia thinks of her mother, the gang will also be thinking of Katherine – and how they could save Elena from the evil doppelganger. Stefan, Caroline and Matt will come up with a “desperate new plan,” and Bonnie and Jeremy will be forced to turn to their new (resistant) witch friend, Liv, for help.

Meanwhile, Damon will still be battling his inner demons as he tries to fight off his urge to feed on vampires. But the need for revenge will outweigh his desire to keep his friends safe, and the Salvatore bad boy will bait Tyler until he sets him loose … giving him the opportunity to chase after Dr. Wes.

By the end of episode 15, Caroline and Tyler will “come to a new understanding,” and Bonnie will learn a “terrifying secret that will threaten the lives of all her friends.”

Episode 15 of “The Vampire Diaries” will air on the CW on Thursday at 8 p.m. EST. What do you think will happen in “Gone Girl”? Let us know your thoughts in the comments section or send a tweet to @AmandaTVScoop.

For more scoop and spoilers on “The Vampire Diaries” follow Amanda Remling on Twitter - @AmandaTVScoop.