Sister Princess
Genres: Comedy, Drama, Romance
Type: TV, Episodes: 26
Aired: Apr 4, 2001 to Sep 26, 2001
Studio: Zexcs
Source: Light novel
Rating: PG-13 - Teens 13 or older
Synopsis:
Wataru Minakami is a top student who failed his high school entrance exam because of a computer glitch. He later discovered that he was accepted to Stargazer Hill Academy, which is located at a mysterious place called Promised Island. At the request of his father, Wataru is whisked away to the island, and before he can settle in, a dozen of cute and charming girls start to flock him and claim to be his younger sisters. As Wataru gets closer to his newfound siblings, a deeper mystery as to why they were sent to the island comes to play. 

(Source: ANN)