Dick Grayson was fed up with Batman, that's true, but he was also tired, tired of always being treated like a kid, tired of keeping secrets, tired of fighting his inappropriate feeling for his best friend, just tired. At sixteen Dick left Batman, and he also left the team, he wanted to be his own hero, work by himself with out living under the shadow of the big bad bat, and he was also running, running from the feelings he wasn't supposed to have.
Five years later he gets an offer, the team wants him to join, except they don't know he used to be Robin, and he's not about to tell them.
Dick Grayson, Ward of batman, is what the young justice describe: strong and cunning. He may crack jokes and have a bad child hood, but he has always been strong. When a mission goes wrong, the team gets beat and Robin gets kidnapped by Deathstroke.
When the team awakens by the justice league, no one knows what happens or who took their little bird. They searched for him for three years before they gave up on their search, accepting his death. In those three years, Death stroke had broken Robin. When Robin failed a mission... well let's just say he has a temper when it comes to failure.
Robin finally escapes the torture of the experiments and uses his new found power to guide his way through to the mountain. Because of the constant serum input, he is blind. Finally reunited with his old team, the team finds how secretive and broken Robin looks now and what will happen if his old master wants him back? How far will Deathstroke go to get him back? Also can the team bring Dick back from his lowest point in life? Will they be able to fix him after the mental and emotional abuse from Deathstroke, or will he be broken and lost forever?