Ethan is terrified of the dream realm, his older sister Isla finds it exhilarating. After months of begging, Ethan finally agrees to dream. Soon after, Ethan is forbidden from returning to Somnium when he becomes injured. It's not long until the children rationalize breaking the rules.
Fulfilling a piece of their mother's prophecy, they unintentionally bring a dream into the real world. Ethan and Isla struggle with how to fix the mistake without alarming their father. Newly discovered abilities become the key to keeping the dream hidden.
As secrets are finally revealed, the children realize they aren't the only ones with something they've been concealing. They must all come together if they hope to discover the darker forces at work against them.