Sora-iro no Organ

In order to save your cousin, who's been sucked into a mirror, you decide to jump into the mirror yourself. You find yourself in a strange, beautiful world of fairies. As you work through the game's storyline, you'll take part in interactive conversations. The game includes an "encore mode" which allows you to view previous event scenes and listen to music that you encountered on your adventure.

[From GameSpy]