In the previous episode, everybody thought Raven (Lindsey Morgan) would die in the hands of Clarke (Eliza Taylor). Thankfully, Raven survived but the group's happiness from being able to survive ALIE (Erica Cerra) and her lies might be shortlived once they reached Arkadia.

The group learned that ALIE was just trying to frame Raven and wants her dead above all else because Raven holds the information that the only thing that can defeat her is a second AI. 

After escaping ALIE's clutches, the group decided to go back to Arkadia. However, it might be a fatal move which could cost all their lives. 

The promo clip for episode 12 of season 3 shows the group going back to Arkadia minus Lincoln (Ricky Whittle). When they reached the place, they were surprised to see that it looks like a ghost town, according to Octavia's (Marie Avgeropoulos) observation. Clarke agreed saying, "It's like they just got up and walked away."

The trailer, however, showed a group of people going through the Arkadian halls with murderous looks on their face and wearing Arkadian technology - night vision goggles. There are speculations that these mysterious men are - in fact - Grounders.

As they marched throught the corridors, their faces looked very upset and it seems like they have one thing in mind - hunt and annihilate Clarke's group. 

Then a scene shows an unidentified enemy strangling Octavia while another one hurled Jasper to the floor. The once deserted area  is suddenly filled with chaos as Clarke's group flee for safety from whoever are trying to kill them. 

Will they all be able to survive the onslaught? This is just one of the questions fans are asking. Other hanging issues that needs an answer is whether Raven is telling the truth or not. Will these questions be addressed in the next episode? 

The next episode is entitled "Demons" and will air on Thursday, April 21 at 9 p.m EST on CW.