When twelve-year-old Arianna learns an asteroid threatens to wipe out Earth, she's terrified. But the impending disaster vanishes as mysteriously as it appeared, leaving her to wonder if it was nothing more than a strange dream. What's more mysterious is discovering her eleven new best friends shared a similar experience.
Together, they travel to the woods behind her new school to investigate the details of their shared dreams, only to discover it's all real. Gifted with superpowers and given a terrifying task, the girls work together to fulfil their promise. Then one girl goes missing, and the remaining eleven must do everything they can to bring their friend home.
Transported to another world, they encounter wild creatures, strange lands, newfound friends, and a villain determined to destroy everything to steal the source of the girls' powers. Time is running out. They must rescue their friend, save the day and return home for if they fail, more than Earth is in danger. The fate of the entire universe is at stake.