Synopsis
Wataru Minakami, an outstanding student, fails his high school entrance exam due to a computer malfunction. He later finds out he has been admitted to Stargazer Hill Academy, located on the mysterious Promised Island. At his father's request, Wataru is sent to the island. Before he can get settled, a dozen lovely and charming girls gather around him, each claiming to be his younger sister. As Wataru bonds with his newfound siblings, a deeper mystery begins to unfold about why they were all brought to the island.