There really isn’t anything that makes Detective 512 (March 1982) a “special” as such. There is a decent Batman tale, by Conway, Colan and Janson, and a lame Batgirl story that I am not going to write up. Instead of the normal letter column, there is a text history of Detective Comics, but nothing to put this on the same level as issue 500.
The story is continued from this month’s issue of Batman, and for the next couple of years, this would become the standard pattern, with storylines running back and forth between the two books.
Vicki notices that Dala did not show up in the photos she took of her and Dick (in the previous Batman – last time I will say that).
Batman is busy rescuing Robin from his deadly dangle from a bridge, left there by Dr.Death to delay Batman while the evil doctor prepares his super allergy to infect all of Gotham with.
Rescue completed, Batman catches up with Dr. Hellfern. He tries to get the antidote from him, but Hellfern is being a jerk, so Batman douses him with his own allergen, forcing him to reveal it’s cure.
Not a bad re-working of Dr. Death, but it wouldn’t grab much interest, and the character would go back into dormancy for another couple decades.