A reunited Harris family leads the effort to rescue Caroline and stop the sinkholes from happening, only to face forces that threaten to tear their family apart. With Lucas' life on the line, Ty accepts a challenge to win his friend a cure.

When a Survivor is murdered, Lucas and Sam lead a contentious investigation to find the killer. Gavin embarks on a mission to save Eve from the fateful vision he's had of her death. Eve finds herself closer than ever to seeing it come true.