In this week’s episode of The Vampire Diaries. we met Luke (Chris Brochu), a seemingly innocuous “friend” of Elena’s who happened to come back early from spring break. Now, we know he’s not only Liv’s (Penelope Mitchell) brother, but they’re also up to something that’s seemingly ominous for Bonnie. What are Liv and Luke planning?

To take down the Travelers

In this week’s episode, Sloan implied that the Travelers were staying out sight so that they wouldn’t draw the attention of Liv. Pretty suspicious, right? Why are they so scared of Liv, and why is she looking for them? Our guess: Liv and Luke are plotting to take down the Travelers for some reason. Perhaps, it’s revenge. Perhaps, they are part of some anti-Traveler task force intent on stopping thing gang of nomadic witches. Whatever the motivation, they don’t seem to be besties.

To steal the doppelgangers for themselves

Everyone wants the doppelgangers. They’re like the MacGuffins of this season (and series), which is pretty great considering they’re also two of the main characters. Their blood holds immense power for the magical community, and Liv at least is definitely magical. (We assume Luke is also a witch, but we’ve yet to see him perform any actual magic.) Do Luke and Liv want the doppelgangers for themselves? It certainly seems like it in this promo for next week’s episode that sees Liv throwing Elena across a warehouse.

To bring someone back from the Other Side

Word on the street is that trouble is brewing in the supernatural purgatory known as the Other Side, and we think Liv and Luke might have something to do with it. The Travelers are the guardians of the Other Side, and they seem to be all-out avoiding Liv. Bonnie is the anchor to the Other Side, and Liv has feigned an ignorance of magic to get closer to her. Perhaps, Luke and Liv have a family member on the Other Side they’re trying to get back?

To destroy the Other Side

This season started with Silas and his goal to destroy the Other Side so that he and his love, Amara, could live together forever in eternity. That didn’t happen, but that doesn’t mean it won’t. Did Silas have backup in the form of this brother and sister duo? It would feel a bit like a random loose string, but Silas had a lot resting on the destruction of the supernatural purgatory to leave to chance. Would TVD seriously revisit this storyline, or are we grasping at straws here?

What do you think Luke and Liv are up to? Share your theories in the comments below!

The Vampire Diaries airs Thursday nights at 8 p.m. ET on The CW.

Kayti Burt is a contributing writer for Wetpaint Entertainment with a penchant for all things pop culture. Follow her on Twitter and Google+!