The CW aired the ninth episode of the 'Vampire Diaries' Season 6 last Thursday and it shows "Delena" going on a trip into the past which ends with Kai's return, who's ready to cause chaos in Mystic Falls.

Thursday's episode, entitled "I Alone," has Elena and Damon trying to find a way to save Bonnie, but ended up bringing Kai to present day 21st century.

Alaric shows up with the Ascendant and hands it over to Damon. Apparently Damon had Alaric steal the Ascendant from Jo, something she claimed kept Kai in the Prison World, and once the deed was done, Damon made Alaric forget what happened.

Damon, along with Elena, then met Liv and she agreed to send them to the other side to save Bonnie. When they reached the 1994 Salvatore house at the Prison World, they managed to contact Bonnie and said they will wait for her return at the house.

However, with the couple coming into the World, Kai got out and he headed straight to Mystic Falls to find Liv. He was unable to make his move on her though, as Tyler appeared to save her.

Jo, on the other hand, finds out what Alaric had done and the two headed off to Mystic Falls to confront Damon. At the same time, Damon told Elena that he did compel Alaric to do what he did, and also admitted that his reason for coming to the Prison World was for Bonnie, not Elena.

In other parts of the episode, Sarah Salvatore is still insistent on being reunited with her cousin Stefan and used Matt to meet him. However, things get heated when Enzo appeared and Matt told Sara that Tripp was killed by Enzo.

Stefan and Sarah did end up meeting, but she revealed that her real name was actually Monique and took the Salvatore identity when the real Sarah refused. Monique ended up getting killed by Enzo.

For Delena, on the other hand, things come crashing down around them when they find themselves suddenly coming back to present day Mystic Falls without Bonnie.

To make matters worse, Kai destroyed the Ascendant, leaving Bonnie with no chance to get back, and then set Elena on fire. He was only stopped when Damon managed to knock him to the ground with a stick.

The episode ended on a somber note as Elena had to tell Jeremy what happened to Bonnie, while Damon blamed himself over not bringing Bonnie back and then found Alaric and Jo angry at him for what he did. Matt is also feeling saddened over Monique's death, while Bonnie comes to the Salvatore house to find herself still alone.

Kai, on the other hand, is still up and about and Tyler finds the man in his home. Kai is fine with saving Liv's life for a price, and he is looking to Tyler to make a deal.

Whether or not Tyler agrees, remains to be seen.

'Vampire Diaries' airs on The CW every Thursday nights at 8 pm.