Abby is determined to find a way to protect her people from acoming attack by the Grounders, even if it means heading intounknown territory and leaving some captives behind. A worriedBellamy convinces Clarke to go with him to the drop ship,where he and Octavia reveal a dangerous secret. Clarke comes upwith a bold new plan to stop the Grounders' attack, leadingAbby to a desperate decision. Meanwhile, at Mount Weather,Jasper and Monty begin to question the motives of their newfriends, while Dr. Tsing conducts a deadly experiment todetermine how to make use of the captives.
