This Digital Light Novel, Melodies of Yesterday and Tomorrow, contains 200+ pages of extra stories and several illustrations to the visual novel, Reimei no Gakuen.

There are 10 chapters, and each of them is a short story about a main or side character. Prequel and Sequel stories, as well as one that happens during the game when Sheryl wasn’t there...

The titles of the chapters:

1. Sweet Melody: Sheryl Prequel story
   
2. Requiem: Rosaline story that happened behind the scenes
   
3. Mute Panic: Hiryuu Prequel Story
   
4. Blood Oratoria: Fraser Prequel Story
   
5. A Song of Screams: Osamu Prequel Story
   
6. Tuned in: Lagi Sequel Story
   
7. Clumsy Christmas Carol: Aito Sequel Story
   
8. Tender Ballad: Tsurugi Sequel Story
   
9. Lonely Lullaby: Blake Prequel Story
   
10. Anthem for Serenity: Sin Sequel Story
    

It is advisable that you finish the game before reading the novel.