Three cover versions exist: a Direct Sales and Newsstand cover with the same art and 1 variant art cover with a with hologram attached.
This issue is a variant of Robin II (DC, 1991 series) #4 [Direct].
There exist further variants:
Robin [Tim Drake]; Joker; Jack Drake; Alfred Pennyworth; Commissioner James Gordon; Dr. Osgood Pellinger; Bones (henchman); Batman [Bruce Wayne]; Two-Face [Harvey Dent] (Cameo); Riddler [Edward Nigma] (voice-only; cameo)
Synopsis
Robin figures out how to track down Joker's lair. While the police rescue Dr. Pellinger, Robin defeats the Joker.