Sister Princess follows a boy named Wataru who fails a class due to a computer glitch. He moves to a mysterious island named Promised Island where he meets twelve young girls claiming to be his younger sisters. The show focuses on Wataru's new life as he has to juggle between school work and having time for his new little sisters.
Sister Princess is a decent anime. It isn't one of the best and I wouldn't really recommend it. The show is a little eye brow raising at times, especially since Wataru, the main character, seems to like his sisters more than he should... And nothing really happens in most episodes. It isn't very good but you might enjoy it if you like drama anime.