So, to give you a better understanding of the issue (and events after), a little bit of set up is required in this case....
...let's jump in!
Detective Comics 697 to 699
Currently in his private prison on the outskirts of Gotham were the Allergent (Maxwell Veezey) and Charaxes (the former Killer Moth, Neron-enhanced).
Lock-Up then took Two-Face (Harvey Dent) out of police custody into his prison. Batman, his current Robin (Tim Drake) and former Robin (Nightwing, a.k.a Dick Grayson) were on the case, but it was Harvey Bullock and the GCPD who captured Lock-Up....but, they had to free him (with Batman, Nightwing and Robin taking on criminal identities so they could be caught by Lock-Up, find his prisoners, then bring Lock-Up and the other criminals to justice, as no one else knew where the criminals were except for Bolton).
Robin got captured, using the identity of Alvin Draper, and due to a short in the communication system, it took Batman and Nightwing a little time to find him, capture the criminals, including Lock-Up.
Meanwhile, former Gotham Mayor, Armand Krol was found dead of a plague, and Commissioner James Gordon was notified.
Meanwhile, Batman got the call from Com. Gordon, that former Mayor Krol died of a resurgence of the Clench, a disease that recently infected many Gothamites, including a young Tim Drake.
Catwoman 33 to 35
Catwoman was then captured by her foe, Hellhound, who was recruiting her for the Collector, who paired her with Brother Umberto, a former member of the Order of San Dumas (the cult Azrael, Jean-Paul Valley, had battled and been trained by).
It took a bit of convincing to get Catwoman to take on this new job (but Selina's attempts to escape almost got her killed, which also made her a little more willing to take the job).
Batman: Shadow of the Bat 53
Bruce notified Dick of the fact that his Clench virus might come back to kill him. Gordon, Penguin and other Gotham residents reacted to the news that the Clench may return. Oracle (Barbara Gordon) used her information to contact Azrael (Jean-Paul Valley), who gave her a little information about the origins of the Clench, and hints at a possible cure to be found in the African desert from a time when the Order of San Dumas faced "the immortal".
Batman told Gordon that he and his usual crew were leaving Gotham for a bit, while Robin informed Huntress that Batman had entrusted her with the safety of Gotham while Batman, Nightwing and he were gone (heading to Africa to look for the cure).
....whose identities would be revealed in Detective Comics #700.