'The Vampire Diaries' Season 4 Episode 15 Preview, Promo: "Stand By Me"

Last week's episode of 'The Vampire Diaries' was an emotional rollercoaster that ended with a lethal and miserable thud. As the vampires followed Shane (guest star David Alpay) in their quest for the cure, they learn that there is only one cure and in order to reach it, they will have to fight tooth and nail against each other and others on the island.

Shortly after teaming up, Elena (Nina Dobrev), Stefan (Paul Wesley) and Rebekah (Claire Holts) learn that there is only one cure left. Rebekah learns of the predicament from her brother Klaus (Joseph Morgan) who is being held hostage back in Mystic Falls by Caroline (Candace Accola) and Tyler (Michael Trevino). After asking Stefan if he'd give the cure to Elena, Rebekah snaps his neck and decides to make a run for the cure herself.

Back at Mystic Falls, Caroline manages to convince Klaus to help her and Tyler decipher the encryption on the Five's sword. She also manages to convince him not to kill Tyler for what he's done. Although he agrees, Klaus is determined to have his revenge and he tells Tyler that he will only allow him a head start before he hunts him down and kills him. 

Meanwhile, Bonnie (Kat Graham) and Jeremy (Steven R. McQueen) are taken hostage by Shane, who hopes to free Silas from his imprisonment and bring back his wife from the dead. However, his plan backfires on him and Bonnie and Jeremy manage to continue without them. At the same time, Damon is caught by Vaughn (guest star Charlie Bewley), one of the Five, who plans to use him as leverage for Bonnie. Once inside the cave, Vaughn realizes that Damon is no use to him and he attacks him, but is met by Rebekah.   

Vaughn manages to immobilize both Rebekah and Damon as Stefan and Elena make it to the cave. Damon persuades Stefan to follow Elena to make sure she doesn't get hurt. However, an unwanted guest (Katherine) takes Elena by surprise. Bonnie and Jeremy make it to Silas' tomb only to be met by Vaughn, who stabs Bonnie in the back. Jeremy and Vaughn struggle and are met by Katherine, who Jeremy mistakenly thinks is Elena.

Trusting that Katherine is actually his sister, Jeremy is surprised when she uses him to free the cure from Silas' death grip by feeding his blood to the entrapped immortal. She manages to grab the cure, but it is too late for Jeremy. Silas grabs him and after having his fill, kills him. Jeremy's lifeless body is found mere minutes later by his desperate sister and Stefan. 

In this week's episode entitled "Stand By Me," Stefan brings Elena and Jeremy's body back to Mystic Falls after the disastrous events on the island. To say that Elena is besides herself with grief is an understatement, and her state of mind following her brother's death worries Caroline. Trying to help, Stefan reaches out to Dr. Fell (guest star Torrey DeVitto) and Matt, the CW teases.

Back in the mysterious island, Damon is in charge of telling Rebekah the news of Jeremy's death and how Katherine managed to steal the cure for herself. However, Rebekah's reaction will surprise him. The two will also learn "an unexpected bit of recent history from Vaughn," the network teases.

As if Jeremy's death isn't enough to rock everyone's lives, Bonnie reveals the rest of Shane's master plan to free Silas and raise his wife from the dead. They'll also learn of Elena's new plan following Jeremy's death.

'The Vampire Diaries,' S4E15, "Stand By Me," airs Thursday, February 21 at 8 p.m. EST on the CW.

WATCH A PREVIEW FOR "STAND BY ME"