Dick's hallucinations of Bruce get stronger everyday, and all Dick can think to do is suffer silently alone. Until Hank walks in on him in the middle of an argument with nobody, that is.
After all of the Titans leave when the truth about Jericho is revealed, Dick is heartbroken. Deathstroke uses this as an opportunity to get revenge on Dick Grayson one last time. With no-one around to help him, Dick has to face a fight that he's not sure he can win. Disclaimer: I don't own Titans