That was at the end of the BRAVE & THE BOLD run, with art by George Freeman?
I honestly was a bit disappointed with that one, despite Brennert being an overall very good writer. I loved his Elseworlds-ish "imaginary story" of Batman's origin retold in DETECTIVE 500, with art by Dick Giordano.
Brennert did a number of exceptional one-shot Batman and Daredevil stories.
He also scripted several episodes of the Buck Rogers in the 25th Century TV series. Martin Pasko as well!