Play Yo-Jin-Bo: The Bodyguards Today!Anime game for Windows 98/Me/2000/XP/Vista & Mac OS X
This is a very popular visual novel. You play a modern girl who is transported into the body of a princess in feudal Japan whose life is being targeted by ninja assassins. In order to save poor Hatsuhime, you must befiend several rough-around-the-edges ronin types and get them to help you. Yo-Jin-Bo is an innovative game with many choices and potential endings. It has a large cast of interesting characters.
It's compatible with both Mac and PC, too!