Jae-o barely manages to find where his younger sister is hiding, when once again he comes up empty—her trail goes cold. Where did Jaei go after the “Good Mill”? Could the Dark Wolf have caught up with her? Soon, the kids hear disturbing news: strange black birds, like shadows, have appeared on Reed Island. Could it be that Jaei is hiding there? And are these birds connected to the Dark Wolf? Unaware of the threat waiting ahead, Jae-o, Saehi, and the Guardians set off for the island…