It's a race against time as Batman tries to save an old ally from the Joker's laughing gas in <a href="/DenOfGeekUS/?refid=13&__tn__=%2Cg"> Den of Geek US</a>' exclusive preview of DETECTIVE COMICS #995: <a href="https://bit.ly/2R12bGS" target="_blank" rel="noopener"> <span> http://bit.ly/</span><wbr /><span ></span>2R12bGS</a>