The idea I had: 

Three years after the end of the series, the girl formerly known as Terra is attending Murakami High in Jump City. The Titans have left on business, and without replacements when Slade attacks Terra, unwilling to forgive her. As he is about to strike the finishing blow, a masked young man appears and almost kills Slade. At the young man's urging, Terra takes up her mantle once more.

If interested please send me a PM. I shall provide my OC. :D