Cassie pushes through her training, with the witches, stretching her abilities until she believes she is capable of using them at will. After a difficult trial, she learns something new about herself... Rafe experiences a terrible loss. Travelling through rough desert with Selina and Clark, they find their way to Cassie... Once the group is together, Rafe tells Cassie about a mysterious signal coming from southern California, near the L.A. dome. Travelling to investigate, they get more than they bargained for. Will Cassie, Rafe, and their friends succeed in freeing the children from the dome, or will they be thwarted at every turn?