Here is the official 
trailer of the fourth episode, Ye Who Enters Here, that will air on next Thursday, February 4th.
Check out the morbidly awesome trailer below, along with my analysis!
It looks like that Lexa is trying ultra hard to win over Clarke. And Bellamy is reunited with that cute Grounder he saved at Mt. Weather! The gang will be hitting the tunnels head on as well. Everything is happening simultaneously, and I love it!
Ye Who Enters Here airs Thursday, February 4th on the CW at 9/8 CT. Follow Grounders Source on Twitter, and like on Facebook.