The Graysons' return

One night, exactly 11 years after the death of the Fabulous Flying Graysons, a bright flash of light is seen at the, currently empty, fairgrounds. Once it disappears, 2 people, a man and woman seemingly in their late forties, are left in its place. Who are these mysterious people? And what do they have to do with Richard Grayson?

*As usual, I do not own any of the characters. All rights go to DC comics. All images used are from Google and are not mine. I only own the plot.*