Commission for Ankaru.

Octavia wasn't always a musician: she had a past life that she rarely talks about, as part of an organization that researched and developed technology in secret under the watchful eye of Princess Celestia. A life she thought she had left behind; but when she comes across a severely-injured Changeling after the invasion of Canterlot, she feels both a desire to help the creature, and to challenge her own skills as a scientist.
But things become more complicated when Octavia realizes the Changeling is more than just a drone, and how it struggles between the safety of being just another Changeling in the crowd, and the desire to be its own person.