Octavia and Vinyl had a perfect life. Due to their success, they were able to retire early. They bought a house in quiet Ponyville. They had a comfortable lifestyle. With the decision of making a foal, it was almost happily ever after.

When Vinyl dies a month after the foal's birth, Octavia decides to leave everything, including the foal.

10 years later, Quarter Note attains her cutie mark, gets accepted into Sweetie's Manattan School of Music and is well on her way to becoming an accomplished musician herself. It's Octavia's time to amend for abandoning the filly all those years ago. Lucky for her, Quarter is excited at the prospect.

Will the teacher with the striking resemblance to Vinyl Scratch throw a wrench in the works?

Dumb question. Of course she will, but it's not like Octavia can get far there. Eighth Note isn't Vinyl Scratch after all. Eighth Note has a nice life, a different personality, and a beautiful fiancée.