Andy's stuck in the Darkness, but he's not alone. Harry, aka Dash from the previous summer, is there, too, showing Andy more terrors in the world without light.

Meanwhile, Dash, Lily, and Eleanor are desperately trying to figure out how to save Andy. They get help from an unexpected source--Eleanor and Andy's odd and silent father. Frederick leads the kids into the horrific woods of Black Sand Beach, where they must battle the Not Cow monsters.

But Andy can only be saved by joining the two worlds of dark and light--and the horror that brings.